SL1 vs T2i anyone?

Sensors aren't the real differentiators in the Rebel and XXD lines. Everything I've read says so. I just got a refurbished SL1 from Canon and I doubt that I'd be able to tell the difference between photos shot with my SL1 and my 60D (or your T2i for that matter) without looking at the EXIF data. Features account for the difference in cost. My 60D has a better viewfinder (pentaprism vs. pentamirror), more control dials, bigger battery, articulated LCD, and a faster continuous shooting rate to name a few feature differences. Given the SL1's touch screen, I really don't feel the lack of the extra control dials. I do miss the articulated screen for low shots and macro work. Continuous shooting is something I've yet to worry about.

If you're thinking about going mirrorless because of the size, then you'll need to ditch the Canon lenses. I've currently got a Canon 18-135mm EF-S lens on my SL1, which represents ~60% of the size and probably 80% of the weight of the mounted lens/body combo. The 18-135 is not a large lens. Stick a "real" Canon telephoto on the SL1 and the ratio is even more one-sided. The SL1 body starts to look like a remora on a shark. If you want a compact camera, one of the new pancakes (40mm EF and 24mm EF-S) placed on the SL1 will get you a small combo package at the loss of zoom capability.

For me, dSLRs with their instantaneous viewfinders continue to hold the advantage over mirrorless cameras. One day, possibly soon, electronic viewfinders will be fast enough, bright enough, and with high enough resolution that I won't care. Today's not that day.