The nastiest skaven list I have seen has something like
Grey seer, bell
Plague furnace
100 clan rats
70 plague monks
Doomwheel
Abom
Gives no points, offers only game ending threats.
Dont know if that fits under 2000, it was a 2400 tourney.
I was the only one not to loose to him in competition. Almost entirely because shadow is OP.
Slann, 3 disc, cupped, shadow
Scar vet
Priest, cube
50 saurus
20 temple guard, flaming
2x5 chameleons
Ancient Stegadon
3 Salamanders 2 and 1
If I had to go to 2000, I drop the steg, chamelons and 8 saurus, up the temple guard to 30, drop the priest, drop loremaster.
That way you have two death stars, and salamanders as anti death stars. Shadow protects you against ogres, bells, hellcanons etc.