[suicideneil]

In answer to the singlespeed issue, you can just buy the coupler for $18 to lock it into 2nd gear, or you can bolt the dog-shifter to the 2nd gear.

I would suggest a flat spot on the motor shaft, and use a little blue threadloc to prevent it sliding off (just dab a little on the end of the shaft where the pinion and shaft meet).

As for a wheelie bar, you could use the rubbish traxxas version, or Swammie make one I think. NewEra also sell one or two I believe.