USA 3D printer support/hardware/suppliers

All I can find for DIY or customized 3-D printer builds seems to be based out of Europe and it’s driving me crazy. Is anyone here in the US doing anything beyond buying one of these stupid ones off of Amazon as is and trying to mess with it? I want to put together a customized Prusa type printer. I’m just trying to find someone in the US that sells the better parts like I’m finding in Europe, such as a rigid steel frame and water cooled printer head etc. without having to buy from Europe.