I am about to make my own (not so mega dungeon) and detail the process in my own thread - but I am very interested in this one, despite a lack of participation up until now, hehe.
By the way (it just occurred to me, so no, I have not looked at your map) how will you be making the map? Will it literally be hand drawn (and scanned presumably) as you mentioned, or will you be using a program?
I use photoshop when I do some maps (sample), but for the most part they are drawn up on paper/graph as well. I'm always curious when it comes to cartography
Now, where was I... oh yes, reading this all again from the beginning (it's been a while).
If I wasn't already up to my eyebrows in the middle of The Castle of the Mad Archmage mapping, I'd be tempted to sketch something "old school" up in CC3 for this.
It would still be cool to see someone with mapping skills volunteer to jump on board. Maybe try asking at The Cartographers Guild?