Over the last couple of days I have been working on some Black Templars. You'll see them soon enough, but for now I want to show you a squad of renegade Imperial troopers who started out as a Chaos-aligned Imperial Guard Veteran Squad Kill Team waaaaay back in the dawn of 4th Edition, and then moved on to become a Traitor Guard Veteran Squad, before finally actually getting re-equipped and painted up as Tau Gue'vesa'la (lit. human helpers).
The squad originally carried three plasma guns and the sergeant type had a boltgun. Nowadays he totes a standard issue Tau pulse rifle, and the squad has swapped its plasma guns for more rifles and a grenade launcher, because frankly I think the grenade launcher is a brilliant weapon oft-overlooked. I like the way they turned out - a grizzled bunch of survivors and pragmatists, mixed in with a couple of idealists, and all of them fighting for the Tau because the Tau, for all their faults, are slightly better at hearts and minds than the Imperium.
Which is, of course, heresy.