Ok, it's been long sought after, even promised by a few people. But on Friday I got a snow day, and decided to do something productive with it. So I've made a fgd file which contains essentially all the Quoth entities. Try it now, for free, from:
http://www.btinternet.com/~chapterhonour/quoth2.fgd
This is beta quality, it's not been extensively tested (or spellchecked), and there are probably omissions. If you spot what you think is a glitch or mistake, let me know in this thread, and I'll try to revise it.
The enticing selling points:
* All the quoth monsters, with coopflags and teleport flags added.
* Full listings of the available textures in mapobject_grill and func_breakable rubble objects.
* Hints in the rotating object fields to remind you how to set them up
* Undocumented features???
I also read that GTK Radiant 1.5 supports loading fgd files, so those people aren't entirely left out in the cold. Which is probably best given the weather...