xcuse me, isn't this worth to be in the "Fund It" pool?
(I won't tag anything w/o several people agree with me)

Fund it!

Been done. It isn't exactly a first person dungeon crawler, but at least they got the class and battle systems right:
http://www.geocities.jp/aaa_3peso/thLabyrinth/index.html

Yeah, Touhou no Meikyuu was a pretty damn awesome dungeon crawler inspired by Touhou.

Would still love to see one that's directly EO-style, complete with first-person and stuff, though.