Upon looking at Cartoon Brew's recent post, and finding the Lauenstein brothers' website, I now realize that I was in fact being stupid. According to their website, they worked on a number of commercials involving the characters from Balance. I've looked on their website before, so I don't know why I didn't notice this before.
They don't actually list the Sega CD commercial on their website, but this is probably because it's not really worth mentioning. The commercials they do mention are for MTV and several PSA's, which are more impressive than a promotional video for a video game console that failed miserably.
I was watching a tape of Liquid Television recently, and saw the sequence with the Balance guys, and was even going to post about it... but then I read the CB post... so, yeah.