Okay I'm going to start a list of some shops that offer services or parts which will come in handy on your project. There a lot more out there & I will add some as time goes by, but if you feel the need to add some please feel free to do so.
Goopy Performance provides some good items & services, like their rotor housing refurbishing.
http://www.goopyperformance.com/
Defined Autoworks have some serious fabricating skills, great parts & services.
http://www.definedautoworks.com/
Atkins Rotary Great knowledge, good selection in parts.
http://www.atkinsrotary.com/
Mazdatrix really explanation needed, great source for parts & info.
http://mazdatrix.com/
Racing Beat another one that needs no explanation, like Mazdatrix great source for parts & info.
http://www.racingbeat.com/
Speed1 once know as KDR known for great builds & service.
http://www.speed1allentown.com/Home.aspx