I'm not spider, but I ca confirm that you get continuous 1280x720 on a decent 45 mb/s card. I use Sandisk Extreme cards.
Really? Fantastic, I have a Sandisk Extreme 45 mb/s card!
Benlen,
Great plan! I am going to play this weekend. Just ordered the 45 mb/s card Sanddisk Extreme.
What do you mean expanded ML footage to close to 1080p? In addition to the extra workflow there is the data issue. Even short clips take a lot of space to process. So I would assume filming long clips say minutes would be daunting. But will find out 
What I mean david is this: Shooting a 1920x1080p clip with the Canon firmware, then shooting with ML Raw at 720p and in post (After Effects/Premiere) expanding the 720p RAW footage to 1080, or at the very least, slightly larger than 1280x720.
The reasoning is this: there have been many claims from some guys on Youtube shooting with the 650D who are shooting RAW at 720 or less than 720, blowing their footage up in post to 1080, and claiming that because the RAW footage contains so much more data, that even blown up it looks better than the Canon firmware 1080p.
I'm not completely convinced of this until I try it with my own workflow and compare.
I am, of course, intrigued by the possibility! I'm a video student with a limited budget, and at this time can't afford to either upgrade to the Panasonic GH3 or the Canon 5D Mark III (two cameras I really want to get my hands on!)
So I'm looking for any way to increase the sharpness and professionalism of the footage coming out of the 650D.