not absolutely sure but the latest issue of either C&D or motortrend (cant remember) had a whole section on all these funky new trans. options (SMG, Tip, etc...) and how they differed/were alike. Anyway, I could swear that there was another company (or 2) that had similar setups to SMG... again though, i dont remember exactly.
That being said... i've never driven an SMG BMW car but it sounds like a nice option.