As for machining...No everything you could image is readily available. Rearsets, fairing stays, replacement subframes, ect have several sources.
I would like to see someone come up with body work options. Yeah you can get race plastic or carbon anywhere, but replica bodywork or maybe even some cool custom modified body styles is almost non existent. I mean what would you pay to get your CBR or GSXR to look like something different from the other 14,000 examples out there. You can change your paint or bolt on a long swing arm but after that???