Looks like Pentax's weather sealing is pretty decent:

http://tinyurl.com/58p85v

"Took this shot yesterday with a k10d at over 104,000 ft altitude. The k10d performed flawlessly in the harsh vacuum of space at temperatures below-60F:"

that is 32,000 metres and -51c!

full set on:
http://www.flickr.com/photos/arena5/...049987/detail/