Looks pretty nice. Did you create some paths and stoke with texture to create the walls or what?
Having waaaayyy too much fun now...Playing with bevels rather than walls...
Sorry for the threadjack... ask and I'll move these to another thread.
BTW - the background "rock" texture is the stock pattern "java" (coffee beans) desaturated.
Basically, I render the background, and on a new layer the grid as an overlayed (50% grey base) bumpmap, then create a new layer filled solid with the "rock" texture (desaturated java in this case). With grid snap on I carve out the rooms using the mask. Select the mask, make it a path, and on a new layer stroke the path... apply a bumpmap of a blurred copy of the stroked path. In the case of the last with no walls, I just applied a blurred copy of the layer mask as an overlayed bumpmap to the whole thing.
I, for one, don't mind the threadjack. Nice to see somebody expanding on the ideas in that original tutorial. In fact, I can't wait to see what your tutorial is going to come out like.
My two cents are as follows. If you think about the drop shadows they don't really make any physical sense, and that's why they're sort of jarring.
The map is essentially representing a top down view of something that's cut into a solid object. If that's the case, how can the edges be projecting a shadow that's behind and offset from them? Your eye's immediately notice this discrepancy and tell that something isn't "right."
That being said, I really want to try different techniques. Your observation is a valuable one, even if I sorta disagree with it. :)