There's a fellow at xtremeresources that finally hit -100 deg C, with a cascade (two step phase change) system. The name is Baker18.
Otherwise, there's another fellow that is well on track to hit the same mark, and he's outlined in great detail, the work that he's done so far.
Did I link this already?
http://www.icecoldcomputing.com/index.php
(I just thought that our phase change Forum needed some input).