I used LogicalIncrements http://www.logicalincrements.com/ to build a $1000 performance mini-ITX system. It all fits in an Ncase M1, so it looks pretty good too. It struggles a bit at 1080p/Ultra, but it can handle all the rest.

Anyways, try Logical Increments, it's pretty good at giving you a sense for how much what you want will cost.

edit - also don't expect to save much money building from scratch. But do expect to get exactly what you want.