If I'm not mistaken you have to be a member of a professional firm (i.e., Series 7) in order to short the penny stocks. Of course, this begs the question of why anyone would want to , but that's a topic for a whole other discussion...
I've shorted stocks under $5 with IB several times. The margin requirements are different though. I think it's 100% for stocks $2.50-5.00 and $2.50/share for stocks under that price. The margin info on their web site seems to be out of date.
Alot of people are unaware that supersoes does not exist for small cap stocks. For small cap stocks regular old soes rules apply.
Jeffo, Does anyone actually use SuperSOES? All the time. It's an incredible improvement over the old SOES system, executions are almost instantaneous, market-makers can't sit on your order, etc. But it doesn't work with small-caps and micro-caps, so the under-$5 crowd are mostly left out of the party.