KVM and Video Extenders

I'm looking for a video extender / kvm extender / video amplified for a monitor that has a native resolution of 1680x1050. Unfortunately, I can't find one, and don't understand how VGA connections work to make a guess.

The best one I've found is the IOGEAR GVE120 Cat5 Video Extender Kit - Retail $160 @ Newegg.com. It says it supports 1600x1200, but what about 1680x1050?

Sound familiar:

http://zurich.ai.mit.edu/hypermail/thinkpad/2005-08/0327.html