[jrdavid68]

As stated above, do what's necessary to make it legal and make sure that your a$$ is covered.

I know someone who has done this where he has put up the entire down payment. At some agreed upon point in the future, the house is appraised at which time the down payment and some percentage of the increased equity is paid to the person who fronted the down. The owners would most likely re-finance at that point taking some of the equity out to pay the "friend".

Given some of the statements above, I probably have that over simplified, and possibly even wrong. I am not a finance person nor do I play one on TV.