This doesn't directly answer your question, but I'd assume the larger question is "Will adding more or bigger monitors make me more productive?"

The answer is yes. I can guarantee it. I wouldn't recommend spending a bunch of money on a single monitor though. Buy two ~22" monitors off of NewEgg. It won't feel the same as a 27" monitor, but you'll have considerably more space, pay at least half the price, and have some explicit compartmentalization going. The downside is that it's not all the same monitor, and you need hte deskspace. As well as having to buy a cable for having multiple external monitors with a Macbook Pro.

I say give it a try, and return it if isn't as comfortable as you want it to be. You'll still be able to get your money back (assuming you return the stuff in the same condition you bought it), and you can go and try the 27" monitor too.