A friend of mine bought a Samsung Rugby, for reasons much like what you're talking about. He decided that he didn't like Android and is instead planning to go with an iPhone + some sort of hard case.

Broadly speaking, if your plan is "buy phone X only to strip it and reinstall some other OS build" then you're asking for a world of hurt, since most Android phones have various hurdles between you and installing that third-party firmware.

If you can wait until mid-May, you'll see what Google's "X Phone" is all about. I suspect it might be quite attractive. We'll see.