Terrain is not limited to just the terrain formats given there are different types:
Building terrain: Oddly enough stacked buildings can often give the techno atmosphere that some map makers all desire. They can also be used to make eeri shadow effects when made to cloak.
Unit Terrain: Units can also be used effectively. For example for a rroom of pure distortion use extra edit to stack observers all over the room thus giving the effect of distortion for any unit within the room.
Neutral unit terrain: Often just the well used and appropriate appearance of crystals, minerals, or other neutral units can make decent terrain just be sure to not be just throwing stuff around.
Working With What you Got: The terrain builder may seem limited but really all it is time consuming. Continuos overlapping will change the appearance of most terrains. Also after laying the initial block of terrain you can make it smaller, thinner, or even nothing but a thin pole of rock by chosing a lower terrain and peice by peice cutting the higher terrain down.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.