I am interested in building my home and being the general contractor. 
I am wondering if it would be cheaper for me to be the GC and build
myself or buy a modular / manufactureed home.  The problem I'm running
into is that my house is custom and am having a hard time making it
fit into their floor plans.

Thanks

Steve

have you considered a straw bale home?

it is not as far out as it may seem.

I am not a researcher, but am a construction trades/property
development guy.  I pretty much agree with colonski-ga, but with
several other points to consider.
Cheaper shouldn't be the main motivator here.  It's a rare opportunity
to be involved in the construction of your own home, in having the
design site-specific and having a home not pretend-custom from a
pattern book but shaped to your family's growing needs.  Perhaps you
can 'split the difference,' by designing the home's broad strokes, or
as clean-up crew, or personally being the sub-contractor for the
interior painting or landscaping or garage sheetrock or?
You won't be saving any appreciable money, but damn it will feel good
knowing that you did part of the work.  It's why eating food that you
have grown and harvested yourself tastes so extra good.  It's why your
baby always looks just a bit cuter and smarter than your neighbors.
Ok, maybe not the baby thing, but all the rest.
Best of luck to you - synapse666b