Not sure if there are still active terrainers, they all have lives now, never saw anyone active in the terrain board anymore except Keiji and Flad (Although they're just making scenic terrain, not playable). Soooo... i dont think you can find someone anymore.
Anyway, here's the list of the people that i know that you can trust, wishing you luck for them though.
-lord_Turin
-Heinvers
-sonofjay