Whizbang Dustyboots
Gnometown Hero
Other than the fact that it sounds like I need to pick up another Monster Manual -- I don't recall two of the monsters from that list -- this sounds great for my purposes. I don't like the "something mysterious is happening" hook, but I can fix that. Hell, in Ptolus, there's a whole class of people who go underground just because.
And I'm only on page 18 of a word-by-word read and they've already made use of many of these sources. And, while not mentioned in the beginning list, a writeup from Serpent Kingdoms is attributed to something powergrouping down there as well.