Could be less.They owe $170k and would like to at least walk away with $50k.I was thinking of offering them $50k for the deed (which I'll need to borrow).

Success is a process, failure is a choice

From the owner directly with a copy of their statement or from their credit report (Assuming it's not charged off or subject to BK) and both methods require cooperation from the borrower and, at least one method puts you into tremendous legal trouble if you obtain their credit information without permissible use to do so (Like buying someone's credit report on line)?

All that with additional cost depending on the choice made.The people who I am planing to offer the house are people who I have got them on my list of home buyers with pre approved credit letter, or people with cash.

Two cautions: don't borrow through your SDIRA.  

You should borrow all of the money that you can and invest in stocks.

If the deal is too thin to support a hard money loan and/or there is not enough borrower skin in the game to recoup your capital if things go awry, then you can lose money just like any other investment where capital is put at risk to earn a return. 

., if "you" are putting down the $100k, surely your Lender will ask whether the funds were BORROWED?

Success is a process, failure is a choice

That would be my #1 choice.