MBA + Extra Displays

Currently I work off of an older 17'' MBP at the office. I'm looking for something that gives me MUCH more screen real estate.

I read an article where someone said they were powering a 27'' display (quite easily) off of their MBA. This got me quite interested, but I'm still a little skeptical. How well does it actually run a big display like that? Does it have the capability to run 2x 27'' displays?

I usually use my MBP for Photoshop & Dreamweaver, some light video/audio editing, and some other smaller apps, skype video/conference calls, and web browsing/apps. Will I be able to do this without noticing a big hit on performance with a MBA + 27'' display?

Thanks for the article. That doesn't really answer my question though. Those say that it can power it, but it has nothing to do with performance.

Am I going to notice a performance hit with the use mentioned above.