If you've not picked up The S'rulyan Vault by +Venger Satanis you should really do so. The product is a high quality made-to-be-printed map in two styles: classic module blue and parchment. You can see samples below. In addition to the map files you get a 20 page pdf chock full of goodness. While it doesn't fill your mega dungeon, it provides you with all the back story and charts of random awesome that you need to do so. I haven't got around to printing the map yet, but I think it'll be worth the cost (and will post pictures when I do so). At 7.00, this is a product I really recommend.