I know why the request to put XP over WIN7 was made. I want to do the same myself!
Reasons:-
1. It is familar.
2. I don't like the re-arrangement of the user interface with WIN 7.
3. I run 4 computers and it makes very good sense to have the same setup/operating system on the lot.
4. I do NOT like Win 7.
Good enough?
I hope it is, so that I can get rid of Win 7.