It may be too late for you (and I don't know if you'll get notification of the reply), but I found your post while researching ThawSpaces. In so doing, I found the following blog as well:
Heath Parker’s blog o’ IT
More specifically:
Playing with Faronics Deep Freeze pt 1 « Heath Parker’s blog o’ IT
wherein the author discovered that the DeepFreeze ThawSpace is actually a file on the hard disk which is legible by tools such as ImDisk or WinImage. This might put you on the right track.
If a version upgrade led older versions of ThawSpace to be illegible by newer versions, you may be out of luck :-(
Good luck!