Hard mount GPS

I want to flush mount a gps in my jeep and need some input on which models to look at. I do not want a hand held unit as they are too small and hard to read. I need some kind of gps i can flush mount in the center console. I also would like it to be able to attach to a pc to update. Finally i need something that has quality off road topo maps along with city maps. Oh and i dont want to spend more then $500. Does anyone know which models i should look at? There are so many and i was hoping you guys could help me narrow it down. Thanks in advance.

Check lowrance they have two models, they are wideley used in desert racing.
You may also want to take a look at the Garmin 276 series its intended for marine use but is great for dash good display size + its garmin