Good luck, 'cos it's not happening.
2560x1600/1440 is strictly the province of 60Hz. Dual link DVI -the connectivity for most (if not all) 2560x 1440/1600 screens (27-30") would probably run into bandwidth problems trying to provide 120Hz 32-bit colour at that resolution.
You may want to revise your budget and/or make a compromise in either size, resolution or functionality. Dell U2711 (2560x1440) $1099 for a 27" (60Hz though), Sharp Aquos 32" HDTV (120Hz, but 1920x1080) for $680, or something along the lines of this Acer (23.6", 120Hz, but again 1920x1080)
Don't forget, DBZ, that most 30" monitors support DisplayPort now which has considerably more bandwidth than both DVI and HDMI - but all the 30s I've seen are still 60Hz.