MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
For other projects, I've bought metric hardware from either Amazon (if I need it sooner) or AliExpress (if otherwise). I think I have most of the hardware on hand, though I'll need to buy the longer M4 fasteners.
I combined the BOMs on the assembly drawings to come up with totals for prints and hardware...it's attached. (For prints, you need 4 "Bracket"s and 1 each of everything else.)