I am going to have problems working out a way to see the Liveview screen, which I use for focusing. I don't want to go to full pc control. Maybe a little thin double glazed perspecs window would work. I am assuming most box users provide remote power as well and do not have to swap batteries. It would be nice to have something small that just cools the sensor.
I love this 'Cold Finger' mod but think it is beyond my capablity:
http://www.dt-space.co.uk/CoolCam450D/
I am also investigating CO2 direct injection into the sensor space which looks promising - uses standard aquarium or beer making gas systems and regulator/tubing. There would be a gas bottle refill charge but a 1kg cylinder could last a month if regulated.