Bryce and I have been discussing creation of special terrain boards for 40K that are playable, but are also high detail and high concept. We had a long rambling discussion and some of the highlights I want to document. My plan for a while is to build a modular tables, with multiple levels for skirmish style games, but big enough to handle a normal or large game.
Necromunda-Style Table: The classic Necromunda table image can be found here.
Below was build with model railroad terrain pieces, but gives a great vertical feel. Found here.
Ork Aircraft Carrier Table: Bryce wants to build more true scale Ork aircraft carrier. Something like the Red Orktober below, but with a top deck. Red Orktober used as a display board at Adepticon provides great inspiration. Found at the BOLS article, specifically this pic.