Hi Thomas,
Like Luis, I have a few thoughts on the questions you raise.
Especially after you have been considered to old by your permanent employer.
Really? Your permanent employer would consider you "too old," especially before normal retirement age, for a job that doesn't involve pulling people out of burning buildings? Here in the US that would be illegal, but I understand that age discrimination laws are not the same everywhere.
How long can we work as consultants or developers in the area of SAP? When are we too old to learn new software versions or even programming languages? What do we do when that happens as I have doubts that this can be done until the age of 67.
I have a friend who only recently retired from SAP ABAP development consulting, and I think he still does the odd freelance job on the side from time to time, you know, to refresh the cruising kitty. I'm not sure of his exact age, but he has to be pushing 70, if he hasn't already passed it. When he was working on a project for us a few years ago, I didn't notice anyone thinking that he was "too old." On the contrary, he was teaching the "young pups" on our staff a lot of helpful tricks that they still use today. It's true he wasn't consulting on the latest, flashiest technologies -- his forte was traditional ABAP and ABAP Objects -- but I don't think that's because he couldn't learn new technologies. I think it's because he found there was still a strong demand for solid ABAP skills.
- Try to go to an inhouse position. There you might also not need to be that up-to-date with the latest technologies. Maybe you can combine that with the next alternative:
- Try to go to support. Again here you can focus on software components which are not state-of-the-art.
I work in an in-house position, technically in a support role, along with the rest of my team. That said, we do a lot of implementation work here, in-house, without consulting help. We aren't always on the latest technologies, it's true, but from time to time we do implement something new, and we're all required to learn everything we can about it. We can't afford permanent consulting help, so we become our own experts. I would pit members of my team up against almost any consultant and consider them to be the better technical and business process experts in their areas. They have years of domain and technical experience that, frankly, only the most expensive and elite of consultants have. About half the team are, in fact, ex-consultants, who "settled down" due to raising families or other factors that made the constant travel a hardship. This includes me. Which brings me to my main point, I suppose.
The usual factor that causes SAP consultants to settle into something else isn't that they become too old to stay nimble with the technologies. In fact, keeping nimble with the technologies, constantly learning, is keeping them mentally youthful and fit. No, the factor that comes into play is the constant travel. Traveling 100% of the time is fun and exciting when you're young, but there's no question it becomes wearying after a while. Eating from restaurants constantly becomes a health factor. It loses a bit of the flash when you've essentially lived out of hotels five days out of seven most weeks. It's fun to go to a new city, but often you spend most of your time stuck in some corporate office looking at fluorescent lights and cubicle walls. Of course, in my non-consulting, non-traveling job today, I still spend most of my time looking at fluorescent lights and cubicle walls, so that hasn't really changed. 
On a side note, I should point out that I still love to travel for recreation, both domestically and internationally. Also, I wouldn't object at all to traveling for work today, even more than a little bit; I just am not in a position right now for it to be constant and all the time.
On top of this, as time goes on, people tend to meet others with whom they become romantically entangled. They start having commitments outside of the flashy consulting job. They get married and have kids. There are PTA meetings to attend, or clubs and community organizations to get involved with. Junior's tenth birthday is coming up and you want to do something special. Suddenly all of this is much harder when you're away from home more nights than not. Eventually a job closer to home, that lets you come home to your family most nights and weekends, begins to look more attractive.
This is probably what happens to most SAP specialists who get "too old" for consulting but are "too young" to retire and don't want to go into management.
- Try to go to management. In management experience is very important, I think, and you don't need to be that up-to-date with modern technologies.
Which brings us to management. I don't think I can add anything here that Luis didn't already say. His response was spot-on. Management is a trade, skill, and expertise in its own right. Not everyone who is a technical expert is necessarily good management material, and frankly, not everyone wants to or should go that route. I was a manager for a while, and it really didn't appeal to me (I did not enjoy having to tell anyone when they were performing sub-par), so now I am in a "technical lead" role instead, which is much better suited to how I like to work. I still influence the decisions we make, just as much as before, but I don't have the personnel hassles on my plate.
It's true in some companies that, after a certain point in your career, advancement stalls unless you go into management. Unfortunately that's true where I am -- I am at the top of my career ladder here. Other organizations have brilliant "thought leader" or "technical fellow" paths that can be an ideal growth route for the technically-minded. And, of course, there's always the freelance option that you mentioned. Other friends have gone that route and are making a hell of a go of it. I might consider that myself, once my daughter has flown the nest and the prospect of potentially not making the money for a little while isn't so frightening.
- Try to do something completely new. So you could move away from the field of SAP and start a completely new career. Of course this could be difficult.
Like Luis, I love this option. If SAP, or whatever you're doing today, has grown a little stale for you, why not try something new? Yes, it could mean starting over in terms of where you are on the "expert" scale, and it could mean making less money (for a while, anyway, until you regain recognition, expertise, or whatever it is that it takes to "succeed" in the chosen new career), but this is the kind of thing that will keep you feeling young right up until you decide you don't want to do it anymore.
In fact, I know people who do this after traditional retirement, sometimes because they need the money, but often because they want to try something new, and being retired they don't have the financial concern about making less money from the job -- they're free to do what they want.
Finally, for perspective, I'm 49 years old. I have been working with SAP for about seventeen years now, and in IT a lot longer than that, and I'm still constantly learning new things. I also branched out and tried something different for a while, after initially starting my IT career, and became an industrial electrician for a few years, before returning to IT. That was a valuable, and perspective-enhancing, aside to my life.
Thank you for your thought-provoking post, and I hope you don't mind my rambling and overlong response to it. 
Best regards,
Matt