I've got access to a machine shop for the next 5 weeks or so...
 

It's got bridgeport mills, a bunch of lathes, a CNC mill, drill presses, all the usual shop shit. All I have to pay for is the metal stock I need/destroy.

Anybody got any prototypes or ideas for me to dick around with?

make decent external wastegate manifolds and sell em on ebay!

How about body braces?

SHUTUP FOO'S!

how about an adapter plate to mount the RX7 transmission to the Miata?

^ VERY yes. Make 6 or 7 (10.) and also some plates to mount the tranny mounting point to the tunnel.

I guarantee there would be some buyers.

If anybody's got cad files, I'll get em machined. :)

Otherwise, that ain't gonna work. I don't have the time or money for R&D work right now. Body braces I'll probably look into. I could actually mill down some solid core tubing for some super stiff bracing, but I dunno if it'd end up being too brittle.

I believe Loki once said that he had the designs for a plate in Bigturbo's FD transmission thread. But I WILL find these files :)

A hub that bolts to the harmonic balancer and allows a common, cheap, readily available trigger wheel to bolt up to it. Also a nifty little bracket milled down to bolt the the engine and allow a cheap, common VR-sensor to bolt up to.