Do your fingers hurt? Having to hold down sprint and crouch are killing mine. But of course, when the need arises, there are heroes that cone to the aid of the downtrodden.
Bunchafunk has created an "Autohotkey" set just for us BFBC2'ers. Now, you can toggle crounch, sprint and even aim down sights! Huge thanks man.

Grab it here. http://bunchafunk.googlecode.com/files/crouch_toggle_autohotkey.zip

For each new aspect of a game that makes it better.. there should be those same inclusions to other games of that genre to bring them all to a higher level. I know that there are detractors that will gripe about "they ripped this off from XXX", but ya know what?!... if it makes the game better, why should anyone other than the copyright holder care? You can recognize an obvious grab from a different game.. good for you and welcome to 99% of gamers.

On another note.. I am curious to see if the BFBC2 community thinks of something like this as a hack, or a cheat..
Head on into the forums and let's hear about it.