would be a mammoth task

I fully agree, it's a lot of work and comes with risk. Why do you want to change a solution that has worked for 12(!) years?? To me it sounds the alternative is (much) more expensive and (much more) risky than the upgrade to Office 2010. I think the best thing todo is to spend the money!

You must work for a non-profit organization, a lousy 10k:))

Cheers

Harry