Surprisingly not a lot...

I would think there would be a pretty big online community to custom truck fabrication, but there doesnt seem to be.

Tell you what call these guys and talk to them. Its a store where I live, Liquid Audio, and they should be able to give more info. They do custom installations for all kinds of vehicles. They are real professional and very nice! http://stanscarstereo.com/

Cool man thanks I will since I'm not having much luck finding any groups or forums on the internet.