I have a contractor that handles about 50% of everything.

I wasted all of that time.These days I say 25,000 non-refundable with a 50/50 split.

Do not settle, finish the case and get a small claims court ruling.

Make sure you follow your state's rules about amount of notice required.

I proposed we split the down payment and closing costs 50/50 in exchange for a 50% stake each in the equity.

Once the property is fixed up and sold, You and The Private Lender will Split Profits 50/50, or whatever the agreed upon split would be.Usual Private Lenders are friends and family and High Net Worth Professionals (doctors, lawyers, other real estate investors)Best Place to find them are at your Local Real Estate Investors Club. 

There are a lot of details the public is not aware of and that's why I set up a specific forum to discuss the rules.

Does anyone have a "standard percentage or rule" they use for setting aside cash for the unexpected during a flip? 

Unfortunately, there are so many rules and regulations around disclosure that it's not worth it to them to talk to you even if they could eliminate their foreclosure timeline by entertaining a short sale or settlement.

Using the 50% expenses "rule" (which doesn't include mortgage), plus mortgage, the return per door looks to average ~$285/m?