While not Dallas, it's available in Garland (or at least in many areas of Garland). I think that's the closest you'll get while still remaining in Verizon territory unless Richardson has it, but I think that's AT&T's area.
Edit: FiOS map with DSLR users available at »/gmaps/fios
I'm familiar with that map. It's in many of the suburbs, just not really in Dallas (as in central Dallas, I mean). It doesn't seem to be anywhere that I want to live.
