For a shorter knob, the LeatherZ Illuminated E46 ZHP shift knob is a popular choice, though fairly expensive especially if you want to keep the OEM shift pattern emblem. But people who have it love it: http://<a href="http://<a href="http...=Knobs</a></a>
As for SSKs, that's actually a separate mod from a shorter knob. Shorter knobs mean somewhat shorter shifts because the radius of the shift arc is shorter, but you'd need an SSK for larger reductions. UUC seems to be a widespread option, though opinions seem mixed.