UPDATE: All of the units at Frys are now sold.
Motorola DTR600 900MHZ 30CH 2-Way Radio Full-Graphic, Backlit Display 30 Floor / 350,000 Sq. Ft. Coverage Area
You will need a minimum of two units. These are frequency hopping units. You also should buy the cable interface to program the units.
Update: Link for the programming cable,