I can't give much advice on electronics placement yet, I've got some fans myself but haven't taken the plunge to mount them so far. As for sources, I've heard of Henry's Helmet Fans (bought mine there, I had excellent customer interactions) and Troopacoola (no experience but I hear the stormtroopers love these)fans systems, and in the forum's continuous sales
fi-8015 sells lots of electro-tronical stuff including fans and speed controllers for fans.
I'm digging your color scheme and can't wait to see how the hammered finish looks in full daylight - I think it's going to look pretty cool.