Too big for first deal? $400k Spec Home

[Caleb Coblentz]

A little back end info- I'm a new agent with goals for my own investing.  I found a great lot with access to the inlet, bank owned, asking $107,000.  I sent it to a builder friend of mine.  He was very excited about a spec home on the property.  His idea was for him to do the plans, build the house at his cost.  I secure financing and we split all profit 50/50.  We would be spending around $300k on the build and should have a $550-650k home to sell at the end.  I know one private money guy.  

Do I:  

(A) sit back and be happy to be the agent on the buy and sell deal and maybe a finders fee

(B) put my wife, kids and house up as collateral for the private $$?

The builder has done several specs.  He laid out his 5 year plan to eventually be able to build homes with our money instead of borrowing.  I think it would be a great project, just don't want  to get in over my head.  Thoughts?