Actually on Feb 10th you may not be able to purchase bikes made for kids 12 and under since the CPSIA is helping "get the lead out".
http://www.atvsource.com/articles/press_releases/2009/013009_blueribbon-youth-atv-ban.pdf
Some "may" be available with a warning label but nost seem to fall under the ban, at least until it's sorted out. A local dealer said the following models are effected.
Honda-TRX90, CRF50,CRF70,CRF80's
Suzuki-LTZ-50, LTZ-90, DRZ-70, DRZ-125/L, DR-Z110
Yamaha-Raptor50, TT-R50E, PW50
Kawasaki-KFX50, KFX90, KLX110, KX85
Polaris- Outlaw50