I am in the same situation as you are and have found only ONE site on the net that offers a 2x1 DVI switch capable of utilizing the 1920x1200 resolution of the 23" cinema displays.
It's $349US and also comes with a 2x1 digital coax/optical audio switch built-in, (no USB for keyboard/mouse though). 2 6ft DVI cables, optical cables and a remote are included in the kit.
"...For computer users, the 2x1 HDTV Switcher is compatible with all DVI-equipped computers and supports Apples line of flat panel displays..."
The company is located in Pennsauken, NJ (right near me) and I'm not sure yet about whether or not they'll ship internationally. I'll call them tomorrow.
wait..I just found a BETTER offering from a company named Gefen that is also 1920x1200 compliant (but only in "single link mode"..??) with audio switching AND also has a 2-port usb switch for sharing a keyboard and mouse.
The kit is (wow) $449US but comes with two 6ft sets of cables(DVI, audio,USB)
FYI, I've purchased through RAM Electronics before and I highly recommend them. I had a good experience with them, a real person responds to their emails - and rather quickly at that.