I've attached a complete rewrite of the Wikipedia linking code. It's a little more modular, a lot more inclusive and a bit smarter than before.
I am definitely still open to input (Haris ;-)) on my coding technique and anything that can be done to improve the command. I'm just getting my feet wet with Ruby, regular expressions and TextMate in general.
If you're currently using the command I distriubted previously on this list, Brett Inc. "strongly urges it's users to upgrade to this latest release".