This has been discussed before in this thread: http://forums.netstumbler.com/showthread.php?threadid=727

I see from your page, that you went through quite a few bit to track these down. In the original thread, it was suggested going direct to a city garage or radio shop to look for mounts. You took the long way, but ended up there. :-) Very nice setup though!

Cheers,
Thorn