@Steven RofferI have read a million post on here about lease option assignments and owner finance type deals and when it comes to pure knowledge about putting these deals together and the legalities behind it @Brian Gibbons knows his stuff and is extremely helpful.

Also have excellent credit, although that does not seem that important anymore. lol If your net positive cashflow from the rentals, using the post-refi mortgage payment not the current one, is 2.5x your personal housing expense and you have no consumer debt (such as if you pay it all off with refi proceeds), there's a chance it could be done based purely on the rental income, as a Fannie loan.

Owner just has a note/debt pure monetary charge, no legal ownership at all. 

Lots of cash buying in the area.I have also seen some financing buys that must work out to be pure equity/appreciation gambles in that area.In the event that you DO fine a price point that works you will likely have to compete with a favored cash buyer.

Purely negotiable, what did your accepted contract say?

I realize my post is a bit different from the pure investor stand point, but I thought it may help give you some insight. 

Even in this bubble, there are investing opportunities out there.Taking out a HELOC purely to cover an anticipated future shortfall in income, will never get you "bigger pockets"!

Since you didn't provide many details, the answer to your question is really "it depends".However, I will say from a pure financing option point of view, I am a big advocate of home equity loans (used correctly). 

The next owner might see more value in the land in they can go either pure commercial or mixed use.But man I gotta tell you, this is a VERY speculative deal here with a ton of risk that you could get stuck with it.  

Good luck, ask lots of questions - this site is pure gold!