So no, that doesn't work. What does work and keeps our customers happy is making sure that what we have works with what versions they get from their vendors.
TeX is not just for desktops. It is a wonderful part of an automatic document generation system.
In case you are wondering what we are doing, the project is LedgerSMB (http://www.ledgersmb.org) and we use TeXLive mostly for generating PDF invoices, purchase orders, etc, along with Perl modules like Template::Plugin::Latex (unfortunately XeTeX requires hacking some of our dependencies currently :-( but that's not the TeXLive folks' fault!)
Anyway I think we are still supporting TexLive 2007.....