Finding one shouldn't be too difficult, you'd be surprised how many of us are still out there :) Not too many games won't run on Win7, including Unity-based games as a matter of fact... But I understand it may be something with their engine and a problem to fix. Perhaps you should contact them and call them racists. I appreciate the effort but honestly still doubt that you'll have it fixed. Be the hero and prove me wrong :P
Edit: I didn't see Whale's reply, maybe there is still hope hehe