Okeydoke. Bear in mind that these patterns are optimized for print rather than screen, but here's a downsampled (144dpi) .GIF file that shows it pretty clearly on the screen, accompanied by a full-resolution 600dpi PDF version for print.
The method is pretty simple stuff:
(A) Convert dungeon map into a simple white-on-black map (white for open space, black for solid earth).
(B) Run a routine to blur out the edges and mark off the griddable areas (one-click Action).
(C) Drop it through a pattern, in this case a little home-jobby I keep around for Uresia projects (which is what this particular routine was built for).
So, very similar to how I do my island maps and such ... the main difference is the nature of the edge-blur, which I'm randomizing more heavily for the dungeons, and the grid.
Thanks for not minding me playing with your map. It's a good way for me to wake up (had a long night ...)
(Obviously, it still needs the full treatment: labels, perhaps a spiffy logo, etc - but even as a raw conversion of the map lines, it's still kinda nice) ...