Jeez, that's 3 of us from St. Paul here. Some kind of geek density thing, or just that many lurkers with only locals responding?
Anyhow, I go outside in the morning and start my car. When I do this, I leave the glass storm door slightly ajar (it's a pain to close, so when I'm only out for a minute I just let it sit about 1/4" open). It only takes about 30 seconds for the window to frost over. It's a cold surface and warm air.
You'd be looking at the flip side - a warm surface and cold air. Honestly, I don't think you'd have a problem with condensation right away. But later on - like after the PC had run for a while and was then turned off, some of those parts would now be cold, and THEN you'd get condensation once the warmer house air was allowed to get in - maybe even enough for water droplets.
It would be fun to play with, but it would be a lot of work, and you'd have to rig and unrig a bunch of stuff to keep any damage from happening. Wouldn't be friendly to use on a daily basis.