Hi Ruben
Experiences - In my first hand experience is SAP BI Quality system (from Windows 2003 /MS Sql 2005 to windows 2008 Enterprise server with MSCS / MS Sql 2008 R2), and we want to migrate all production(SAP BI,EP & XI ) systems to HA environment.
For HA Environment follow the steps
1. Exporting the source system using homogenous system copy (either backup/restore or detach/attach method)
2. Install the HO servers with windows OS 64 bit enterprise edition with latest patches.
3 Fail over cluster service installation and configurations
4 MS SQL (2008 R2 or 2005) cluster installation as per the installation guide
5. Central services instance for ABAP installation.
6 Central services instance for JAVA installation.
7 First MSCS node installation
8 Database Instance Installation using backup restore method
9 Additional MSCS node installation
10 Enqueue replication server installation for ABAP in Node I
11 Enqueue replication server installation for JAVA in Node I
12 Enqueue replication server installation for ABAP in Node II
13 Enqueue replication server installation for JAVA in Node II
14Central Instance Installation in Node I
15 Second node installation as per the installation guide
16 Post processing steps after system copy
Suggestion - Since you are using the Microsoft platform it is easy to do the system copy method either Backup/restore or Attach/ detach,
Advice - To get the first hand experience better you can try out in your new hardware with different SID and also you follow the links which i already communicated in my privies message
Thanks
Ram