For bluray, it's recorded in the exact same framerate as traditional bluray, but instead of being 1920x1080 frames, it's double height plus a 40-something-pixel buffer, with the top being the frame for one eye and the bottom being the frame for the other - so ending up with 1920x2215 or something wacky like that.
However, keep in mind there are two different frequency numbers:
1) framerate of the recording - the rate at which the picture in the source media changes from one picture to the other, and
2) refresh rate of the display - the rate at which the picture on the screen re-draws itself.
The thing is, with active shutter solutions, between each frame the eye sees a "black" space. Our eyes will perceive that as flicker if the refresh rate for each eye drops below 60hz. Thus, the display must refresh at 120hz or higher to display active shutters without flicker.
As for disc space, back when bluray and hd-dvd were fighting, most held the belief that a standard movie in full hd would have no trouble fitting on an hd-dvd as long as the extras were kept to a minimum. So based on that, a 3d movie shouldn't have trouble fitting on a bluray, they just may have to cut back on extras. Not to mention, I seem to recall reading that there was still plenty of capacity for layering if it becomes necessary.
Sorry, my last post was a meandering mess... My point was that to bluray player or tv manufacturers, the additional cost to support 3d is extremely small, so there's no real reason for them to drop the standard, even if it's not being adopted.