A quick comment about L-plates:
If you do go for one (I live by 'em, I find precise positioning with any tripod head harder for portrait shots otherwise) -- take a look at the Kirk L-plate for your camera as well. I'd had RRS plates in the past, and they are unquestionably well-made, but the Kirk plate for 7D seemed (and I'm comparing plates from different cameras here so you should be a little skeptical) excellently constructed as well, just as strong, and (because of design) even lighter.
--Joe