I've never heard of any software able to spoof a MAC address on a BB. I think it comes down to the fact that there aren't too many people in the market wanting to do something like that. If this is something you're interested in doing just get a windows mobile device. There are plently of programs out there you could use to get the educational experience you're looking for.
Posted from my CrackBerry at wapforums.crackberry.com
bumping this topic up -- 'new' current reason to pay attention to transmitting mac address over ipv6. From what is posted here already, it would seem that BB is affected in the same way?