Hardware to switch Dual DVI monitor setup between PC & Mac

[Abstrakt]

I have a specific setup, although simple.
1) Mac Pro w/ dual monitors, used for Audio & Video
2) Custom PC w/ dual monitors, used for CAD and other

All I want to do is switch my dual monitors between the PC and Mac.
I don't need to share keyboard or mouse, those are separate, simply I want something with 4 DVI input and 2 DVI outputs so that I can switch my dual monitors between my PC and MAC setups. I can't find anything. I've googled forever and searched at stores... what's the deal?

 

[Abstrakt]

The only solution I have found to this point that will allow me to hot swap between two dual monitor setups is the Iogear GCS1642, although the thing is $350. Unfortunately I don't need a full on KVM since I use custom keyboards for both the PC and Mac specific to the software they control, but I could share a mouse if it came to that, and there's an aux USB input that could be used for a webcam or something to share between both systems.

The only solution I can think of is to use two 2in 1out DVI switchers at about $35ea, but I'm not even sure that would work...