Help on partnership dynamics with spec home builder

[Colin Perry]

In a few hours I'll find out if my upset bid for a trustee sale remains intact.  If so then I'll be moving my family into a great new property (yes I've done my homework on the auction process).  If I am fortunate enough for my bid to hold, then I'll want to sell my existing residence.  I have a great lot in a desirable "inside the beltline" (preferred area for tear downs) location.  The lot value could be worth nearly what the home would get on the market right now.  I'm contemplating contacting a handful of active home builders in this niche market to explore the idea of a partnership in which I would contribute the lot and they would put in a new home and we would potentially split the profits.  

There are plenty of hurdles and risks to clear in such a partnership but if you know of them please help me list them.   Also, how could I factor the current mortgage payments into the partnership valuation (assuming there is a viable deal to be had).  From a financing perspective I'm guessing no lender would loan the builder money without him holding the note.  So I'd have to sign over the note to the builder and hold a second?  I'm out of my league here but if you have experience in this arena please let me know. 

Thanks!