In my mind, since the "official" version of the setting has been killed off, I've branched off with my own alternate setting. In this "Althammer" (as I'm referring to it) I've got several tiers (size & importance) of armies, and a couple of them fit the "Empire" theme, I think.
One being Marienburg, which I played in WFB 6th - 8th editions, and continue to expand upon in a "rules-neutral" sense. (I've used them in KoW and WFB3 since the "official" death of the Old World.)
The other is my own concept, the Jackrabbit Trading Company, a merchant company from Marienburg's hinterland (the Wasteland -- specifically the Little Country) that has a significant armed presence and becomes involved in regional politics/uprisings as well as following the original mission of guarding the overland trade caravans.
I'm currently prepping minis for a small force of "hill folk" -- rural rebels, bandits, etc. from the hill country on the Wasteland side of the Grey Mountains/Pale Sisters. Imperial hillbillies?
I'm increasingly fond of the idea of "regiments of renown" and have been thinking about painting up some other Empire/Old World regiments... a former Nordland regiment that's turned mercenary, official DoW (I still have unpainted Pirazzo's Lost Legion & the Birdmen of Catrazza figures), maybe some more homegrown regiments.