Some of the Aprilia, Derbi and Italjet scooters are pretty cool.
Plus, both Aprila and Derbi have scooters masquerading as motorcycles... the Aprilia RS50, Derbi GPR50/GPR50 nude or Derbi Senda 50 which is a super motard.
They also make big-bore kits (75-100cc) for the RS50s.
These seems like they might be decent if they aren't blowing smoke about their reliability. Good prices if you don't mind doing your own paperwork and setup.
gsmotorworks