If you haven't already, I suggest you read a book or at least a few websites about netiquette. The Internet has many etiquette rules, and if you don't follow them, people will teach you how to behave properly. In general we presume people do it because they don't know, so we tell them. Excessive use of bold or caps indicates yelling or shouting or an egotistic individual who thinks too highly of themselves. None of those are very appealing to read.
But back to the main subject. I have a Canon T2i and the theoretical max is 30 minutes of record time or 4 GB. I haven't tried at 720p, but at 1080p 30 fps that gives me about 12 minutes before I reach 4 GB. Afterwards, I have to wait a few seconds for the buffer to clear, and then I'm good to go for another 12 minutes. At 720p, probably the limit would become 30 minutes instead of the 4 GB.
After a few of those, the camera starts complaining about the heat. But maybe that's only because I'm currently visiting in Mexico, I'll see if it keeps doing that when I'm back to Canada next month.
I currently have a 32 GB SDHC class 6, which is what the booklet recommends, but I see a major flaw: the camera lets me record images while it's recording video. With a class 6 memory card, if I take 1 or 2 pictures, the buffer runs out and the video stops. Next on my purchase list is a class 10, which this country doesn't seem to be selling. But from the description of it, class 10 SDHC or SDXC cards were made to record video + take photos at the same time.
Cameras: Canon EOS 6D, Canon EOS Rebel T3i, Canon EOS Rebel T2i, Canon S90
Lenses: Tamron: SP 24-70mm F/2.8 Di VC USD, SP 70-300mm F/4-5.6 Di VC USD, Rokinon: 8mm Fisheye cine, Canon: EF-S 18-55mm f/3.5-5.6 IS Lens, 75-300mm f/4.0-5.6 III, and EF 50mm f/1.8 II
Retired camera: Fujifilm Finepix s700