I was figuring the standard Inquisitorial stuff, iincluding inducted guard or marines.
Also the possibility of xenos forces, select one alien codex, you can choose troops from that list without restriction, for each troop choice you can take 1 choice of elites, fast attack or heavy support. If you include a rogue trader as an HQ choice, you can pick from more than one alien codex. Allowabble choices are eldar, dark eldar, tau, orks. Down side of this is the whole army gets labeled as radical, and loses access to conservative items.
You have the deathwatch, in all its glory. I see them mostly as a special forces kind of unit. Troops they come as presented currently, but with no captain, and a limit of veterans, more than that they become elites. I would guess 3. Deathwatch bikers for fast attack. Heavy support would be a squad equipped with the sniper pattern bolters, maybe a BS of 5. Squad size 1-5, infiltrate, squads of one can access additional gear. Another possible elites choice would be a squad with combi-weapons, and the skill to use them with true grit. HQ is the deathwatch squad as presented currently. Deathwatch would be limited availability in radical armies, perhaps troops only. Absolutely no dreadnoughts, the bodies and geneseed would be returned to their chapter.
Finally, for conservatives you can have the adeptus of mars. Skitarri and servitors as troops. Electro priests for the unpredictable elite nastyness. Some "flexible" vehicle rules, kind of a mini VDR. Leman Russ chassis, choose turret weapon from list A, hull weapon from list B, sponsons from list C, and upgrades galore. None of it available to radical forces.
Similarly wargear availability would be cut down the radical/conservative line. Alien weapons for radicals, techno gizmos for conservatives. A resurection of a much toned down Vortex Grenade, something like vortex of doom psychic powere, 12" range, gets hot. No duration, no eating anyhing it touches... stasis grenades, MIU, other nifties from the Inquisitor rules...