If you haven't already been overwhelmed by the wealth of material in The Radical's Handbook, here are three more Radical Career Ranks to consider... there's a lot crammed into a mere eight pages and, given that this is a freebie, it is as well-presented as material you're expected to pay for - impressive detail and care here.
First up is the Demagogue. Any religion worth its salt has some of these: people who can sway an audience with words alone, so it's useful to know how to make one within the context of Dark Heresy... even if they are often regarded as dangerous characters that must be controlled and monitored. There's a lot of potential for some fun role-playing with one of these, especially for a player who enjoys holding forth themselves.
Next is the Infil-Traitor, an unfortunate who's been captured and mindwashed into becoming a 'sleeper' assassin, triggered by a codeword or event to become a merciless killing machine. Now you might ask, where's the fun in playing that - although it's something useful for the GM to tuck away for an NPC - but the neat thing is, if you pick this you play someone whose programming is flawed and get the chance to break out of it and regain complete control of your own mind. It's not something to force on a player, and should only be attempted with mature groups who can handle this level of intensity and potential conflict... but could result in some powerful role-play if handled well.
Finally, there's the Saboteur. This is possibly a polite word for a terrorist and you again might question the place for one within Acolyte ranks. Sometimes, however, dark and terrible things have to be done in the name of light - and the ability to blow things up and cause confusion and fear often comes in handy.
Some interesting stuff here, worthy of consideration for your game.
[5 of 5 Stars!]