remember.. a lot is allowed.. civillian and military, from scale 1/76 and up...
so, you could buy a fujimi kit, and make one of the complementary cycles that come with some ( either a harley, BMW or Zundapp )
or, you can go wild and get the Revell Satte Literschussel ( German comic figure Werner's bike, 1.444 litre engine lol )
Or, I recall the Airfix Wallace and Gromit tricycle... which would do nicely aswell...
The possibilities are endless

Best rule though: have fun
