Hope this is not out of context:
two months ago we started FabHub.io, a directory of (professional) digital manufacturing service providers. The platform still needs plenty of work but we have more & more fabricators and makers signing up organically. It's a free listing site & quoting engine.
It should become a good source to find professional makers for Wikihouses around the world.
We've developed FabHub as a source to develop a network of makers for
OpenDesk.cc - commercializing open source furniture (and our day job to
pay the rent).
Second source I can recommend is
themakermap.comIf you're a maker I suggest signing up on both - each have a distinct audience.
Ian