Just the other day my friend pointed out that the ship name for DeWitt/Dominic (from Dollhouse, whose fandom is so small it doesn't really use portmanteaus) would be Demonic. Which I thought was just awesome.

For terrible ones, absolutely anything at all from the Buffyverse fandom. Some particularly "great" ones: Spawn/Dike, Fuffy, Spander, Spillow, Fawn, Frunn.