I did my fairly large kitchen for about $50 in materials and it's held up great for two years of use.

As with any contract though, you'd need a very specific scope of work, material qualities, etc.

Now here is my two cents - a home's square footage is one thing to compare on a CMA, but there are other things too- updates, materials used etc.

Like a @Brian Burke for example who is a foreclosure expert in your market.. then there probably is not the kind of money in it your thinking there is.picking up the pieces of a failed major rehab can be all sorts of problems.. at least the foreclosure will wipe out material men liens in CA. 

It has been built with several different types of materials, and seems to be held together by caulking.  

You can find all the contractors you need -- just go to Lows or Home Depot 5:30 in the morning and talk to the folks buying material for their next job - negotiate Charles 

When you're ready, here are some good DO's and DON'Ts when getting bids:DOWrite out a detailed scope of work that outlines exactly what you want to do.Clearly define what (if any) materials you will buy and what the GC will supply.Get multiple competing bids.Check GC references, call past clients of theirs and possibly even ask to see their work.Closely analyze each bid and ask a lot of questions on things that are not spelled out.Ask each bidder for an anticipated schedule for the work to be completed.Ask each bidder about their desired payment terms.Sign a contract/written agreement with the successful bidder.DON'TWaste people's time if you're not serious about hiring them.Walk the job with competing bidders at the same time.Assume that all GC's will see the work happening the same way.Pay large sums of money in advance unless it's justified.  

I would not recommend doing the design part yourself unless you are extremely familiar with current trends, picking materials, coordinating colors, understanding product specs, and building code for that matter.

Your General Contractor may have used Subs and you should cover your assets and make sure he has all those subs paid and you have lien waivers to back that up, or other documentation that similar from him, just because they are licensed doesn't mean they paid all their subs off or suppliers for parts and materials.

I've been reading a few of the books and materials; they have been very informative.