I've been working on my Skaven recently (much to the chagrin of my Terrorgheist). I picked up a second Doomwheel, and finally assembled the Rat Ogres from my Island of Blood starter set. The packmaster Skweel Gnawtooth is a must-have to accompany Rat Ogres; one of his abilities bestows a mutation to the unit that can result in poisoned attacks, extra attacks, or regeneration.
I was having trouble tracking down a model, so I decided to convert my own. The body is based on the Skaven warlord in the starter set, with arms pulled from one of the champions. The whip is from an Orc model. One of the classic metal giant rats and a bunch of plastic rats make up his verminous bodyguard. Some sculpting on his robes and the rocks finish off the model.
Skweel gets the same quick-and-dirty paint scheme as the rest of my Skaven.