Could someone clarify then this sRAW, is this the difference between line skipped video mode vs 1:1 crop photo mode?
There's a feature in the newest Magic Lantern builds that allows you to change the picture quality for photos inside the Magic Lantern menu.
Usually this is only possible in Canon menu. You know, that are the settings like "L" (For Large JPEGs) or "RAW+L" (For Large JPEGs and Canon raw pictures).
And since the Rebel line had only one size for raw pictures, ML added two more sizes: MRAW and SRAW (Medium and Small). They don't work properly but they affect the size of the buffer. And that's the important thing: The normal size of the buffer is 68 Megabyte. With MRAW it's only 36 Megabyte but with SRAW it becomes 96 Megabyte. And with a bigger buffer you can record more frames, even in higher resolutions.
SRAW has nothing to do with crop modes. And it doesn't affect the image quality of the raw videos. It only increases the size of the buffer.
But when SRAW doesn't work on your cameras then 1% probably was right when he said that the 550D is actually the worst camera for raw video. But don't worry, 600D is the second worst

And keep in mind that when shooting in Canon's 720p mode you'll get even more aliasing than in 1080p or 480p mode since it has even more line skipping. It's only usefull if you want to get as much width as possible to keep the crop factor small.