How about phxaz instead of phx?

Don't know about everyone else out there in twitterville, but I use twitter on my cell phone and track my username (tankilo), tweetupaz, and phx.
Problem is, instead of just the traffic for hashtag #phx, I get anyone talking about flights inside and out of phx, and all sorts of sports references.
As twitter grows this will become increasingly harder to handle.
So how about this, instead of #phx, how about #phxaz? I know with a 140 character limit, 2 characters is actually not a trivial matter, but I hope it will prove worth it in the long run.
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