The only way I see Buell/HD in MotoGP is if they did the same the did last time, that is, pay some external company with the required technology to build the bikes and then brand them HD/Buell (in the 70's they were competitive in 350cc world championship)
Though right now I think the return of Aprilia Racing could be first possibility, they are a racing bike manufacturers and sooner or later the 2 strokes will be finally murdered and they'll have no other option than to build 4 stroke GP bikes or disappear.
Also it will be interesting to see of any of the new emerging Asian companies (Chinese and Korean) have interest in racing.
Though right now I think the return of Aprilia Racing could be first possibility, they are a racing bike manufacturers and sooner or later the 2 strokes will be finally murdered and they'll have no other option than to build 4 stroke GP bikes or disappear.
Also it will be interesting to see of any of the new emerging Asian companies (Chinese and Korean) have interest in racing.