I wouldn't have a problem with it personally, as long as it was a Grey Knights legal list and the models were clear about what they represented... but I've been demoted from "Team Fluff" and had to go and play with the much less cool "Team Counts-As" (Coach, Galahad G. Galahad) recently, so you don't have to take any notice of anything I say.
:using Codex: Yoghurt to represent a cyclops:
"Well it's Forty-one Thousand Nine Hundred Sixty-nine OK -
Gotta war across the Milky Way - "
Iggius Popiscus and the Stoogii, "41,969"