On wanting to scale, maybe farming out some of the PM work to someone else to allow you freedom on other tasks. 

Costs will be higher with this route, but it would accomplish your design to not have any one individual "on the hook" for non-performance of the loan.However, I'd encourage you to either be comfortable with the liability in the deal or to not do the deal.  

If you're really building an in-depth list, get back to me again and I'll update you on their(Isbell) performance.

After getting crazy expensive bids from contractors, I decided (naively) to take on the task of being the general contractor myself. 

Am I able to put a contingency on my assignment contract saying I can back out if my buyer doesn't perform? 

You can get into houses with little to no money down, you get an extra pair of eyes validating the deal for you, you have someone looking over your shoulder making sure you and your contractors are staying on task and you don't have your personal residence tied into the deal in any way.

@Kevin Sobilo The property is in a C+ B- area and we have multiple properties performing well in general area.

I has this happen to me and filed a specific performance suit against the seller.

THis way you won't have to 4close if he doesn't perform. 

You can perform a search of cash sales in the area where you are buying (through the MLS for example - that would not cost you anything, just ask a real estate agent) and contact these cash buyers and see if they would be interested in partnering with you or funding your deal.