Hmmmm...California the once125% LTV state.
I'm curious as to why a lender would accept a short sale contract containing an "or assignee or subject to" provision? These guys are wanting to maximize profits. I hate to rain on your parade but simultaneous closings on short sales is a real stretch.
I'm not saying it's totally impossible but, I have never heard of it thru traditional lending. It may be possible with private money on a rehab.
The first issue is the fact that it's short. Where's the profit to fund the transaction. If there's profit the current lien holders are going to want it. In most cases they won't allow an existing owner to make a dime.
As for the new lender....If the property doesn't meet value, traditional lenders won't loan enough on the transaction to create a profitable spread.
The second issue that comes to mind is schedule "A" on the title. Schedule "A" will need to show you as owning the property before you can sell it. You can't sell a property that you don't own. If you add your name to the title prior to the end buyer you become subject to the no profit rule.
Is the buyer selling short due to an upcoming foreclosure? How much time do you have? Does the property need work? How else can you make money in this transaction?
Check with some of the pro's in the short sale forum. Off the top of my head....I may be wrong but, personally, I don't see how you can legally flip a short sale for profit using traditional lending.