I just think back to when I was a kid, had buckets of lego and used to build houses and spaceships.
Why not put that creativity to work and build D&D Dungeons.
Some of the Dungeon Wall Sets you can buy can be pretty expensive but do look cool. Why not just mimic the idea with Grey / Black Lego Bricks.
I agree the idea of making Lego Minis (which although is my suggestion is not what I think the post I linked to was doing, I think they were just being artistic) is a little rough around the edges but expanding the idea to the 3d enviroment of a D&D dungeon sounds intriguing.
You can even make a roof, that whilst made from Lego would have the bottom pieces covered with paper or card so its easy to lift off. That way if your group is entering a room, rather than just have everything open plan from a birds eye view, you can cover certain areas up and even better, pre-place the mini's inside so that when the roof opens up inside is the Monster Group.
Am I crazy for thinking that Lego as a substitute for expensive craft models is a good idea for D&D Dungeon Design?