Two speed BB?
 

I just found this :
http://derbyking.com/Detail/?n=145

Anyone have any experience with these, know how they work, etc?

No experience but looks interesting. Almost like a roholff in theory but designed around the bb instead of the hub (or in effect doing the same thing nicolai does with a hub but nicolai puts in in the centre of the frame and uses a SS rear wheel)...

I would love more info too, I can think of some applications in downhill if it is strong enough (which I doubt there already isn't enough room for bearings in a standard bb as it is)

There is some info on them at http://www.sheldonbrown.com/harris/schlumpf.html and more if you follow the links to the manufacturer's site. They are an internal planetary gear.

In the manufacturer's faq section they specifically say they will not work on fixed gear bikes. The reverse pressure will esplode them or something. Would be great for a 700c coaster bike, though.

As for fixed gear: not to mention it would be pretty hard to hit that button to shift while the pedals are constantly moving.

Coaster brake? I'd imagine the backward pressure from coaster brakes would do the same exploding.
If you meant SS freewheel then that seems OK.

The faq says it works well with coaster brakes, but not fixes.

It sort of makes sense, because the maximum backpressure on a coaster brake is your body weight, compared to your body weight plus the force of your forward momentum (until the skid starts) on a fixed. That would be a lot more, depending on tires, dry road, weight transfer, etc.

Could also have something to do with coasters only back pedaling 1/4 to 1/3 rotation.

I don't know, man, I'm just telling you what the thing says.