We have sequenced around 5000 applications, just about all have been sequenced on Windows XP SP3.
The target OS being Terminal Server 2003 / Windows XP / Windows 7 (64BIT).
We have Citirx , VDI , Physical the VDI build is XP so we have to base the sequence on this platform for compatibility.
There are very few applications we have had to re-sequence on Windows 7.
For example Symantec Vault for Outlook 2010 when sequenced for XP this worked , when tested in Win7 this gave OLE form error. This was simply resolved by sequencing under windows 7.
Mike.