I also just looked up a 6 speed transmission conversion. Phase 5 pipes. DG Carb kits and DG also had what the called a "Pro Kit" which had the carb set up, reed set up, head and of course porting your piston and cylinder. There was a low profile seat for the yt125/175 also.
Nicholson 500x (Project)
Nicholson 185s
Nicholson 110 (That takes an atc70 tank)
Ascott 500 head/350x (Project)
Homebuilt Racer Chromoly Suspension 110 (Ragin Runt)
PK Racing Suspension 70
A+ Inc Suspension 70
AWS Aluminum 90 frame
Hi Performance ATC Suspension frame rd350
Hi Performance ATC Suspension frame 90