Not without some sort of HDMI or analog capture converter which would be kinda pointless when for the same money you could get a dedicated HDMI monitor. That's what you want...
right- which is clunky tethering and useless for focus- which is what I'm guessing the OP is asking about. Try Marshall monitors. They're a bit closer to $500 for the smallest HDMI one's like the 5" but you might find a sale or used one.
I don't see why being in SD would be a problem with the T2i. Any HD monitor will downgrade to SD as soon as you start recording on the T2i (which you probably already know).
However, you have a 7D as well, which doesn't downgrade to SD when recording. That being said, it would be kind of pointless to use the MBP as a monitor because for the 7D, you'd need something that's HD, so you might as well use the monitor for both cameras, making it less inconvienent.
but the build and resolution may be a problem. tis a nice price though.
so how much am i going to have to pay for a decent 7" marshall? or if anyone can recommend another brand? would be good to have one that powers off the 7d batteries