Having far too much free time (and enjoying this Beta way too much 
) I've come up with quite a few faction specific names, based on various tidbits of lore and such. The names are below categorized into each kingdom/empire as well as the units class (my general definition of them anyway, though the names are more or less interchangeable):
Kingdoms
Altar:
Free Legion of Altar (Militia)
Altar Farstrikers (Archers)
Knights of Altar (Heavy Calvary)
Lord Relias's Guard (Heavy Infantry)
Capitar:
Levied Militia
The Duke's Guard (Heavy Calvary)
Walderon's Own Knights (Heavy Infantry)
Gilded Merchant Calvary (Light calvary)
Guardians of Serrane (Elite infantry)
Gilden:
The Stonebreakers (Militia)
The Ironbreakers (Light infantry)
The Wall Bringers (Infantry with high defense and shield wall perk)
The Gold Guard (Heavy Infantry)
Steel Pikes (Heavy spearmen)
Tan-takreet Diamond Breakers (Elite infantry)
Tarth:
Tarthan (Tarthian?) Skirmishers (Militia)
Rangers of Tarth (Archers)
Tarthan Braves (Light infantry)
Gladiators (Bezerker, low armor/high damage)
Irane's Rangers (Elite Archers)
Empires
Kraxis:
Men-at-arms (militia)
Imperial Lancers (Calvary)
Tanacabran Legion (Heavy Infantry)
Emperor's Legion (Elite Infantry)
Dread Riders (Heavy Calvary)
Umber:
Voylin Marauders (Militia)
Herdara Raiders (Slightly better militia)
Spine Splitters (Heavy Infantry)
Morrigan's Wrath (Warg Riders)
Spawn of Calebethon (Elite Infantry)
Yarleth's Scouts (named after a custom character of mine, Archers)
Magnar:
Magnarites (militia)
Slavers of Magnar(Light infantry)
Slavemasters (Bezerkers)
Dark Guardians (Elite Infantry)
Pit Wolves of Imperium (Warg Riders)
Resoln:
Acolytes (Militia)
Wraith Guard (Light infantry)
Seekers of Talax (Heavy Infantry)
Oracle's Wrath-Bringers (Elite Infantry)
Yithril:
Manbreakers (militia)
Warriors (Light infantry)
Havocs (Heavy Infantry)
Beasts of the Fist (Warg Riders)
Warlord's Scourge (Elite Infantry)
Yeah, sorry for the huge post. Like I say, I have a lot of time. Hopefully at least some of these are helpful, if only to give you your own ideas (though I would be thrilled to see some of these in the official release!)
