The Seneschal is much more of a glorified accountant/merchant that does back-room deals, than a quiet assassin/scout/sneak. But the Seneschal is the closest career to a rogue.

Are there any custom careers that take the player down a more interesting path for being stealthy?

built right the senichal can do that job if built right or failing that use an assassin from DH

Sounds like were getting one among the alians to, Both with the Kroot (who are naturaly that way) and with the Ork Kommando. Though to be honest, its not an archetype I miss in this game.

lord inquisitor revan darksoul said:

This (Senechal) is actually the "Rogue" career in RT, they have all the requisite skills by rank 2 or so. For an outright "Assassin" (as in someone wanting to play a death cult or temple assassin in RT) I've house ruled a slightly modified Arch Militant for those folks.

Remember, this may also be satisfactorily addressed within some of the upcoming books which will include alternate career ranks for our Explorers.

-=Brother Praetus=-

I would say just use the Dark Heresy Scum career path and allow them to use the origin path rules as normal RT characters do and then 3-4 of their starting skills at the +10 level instead of the basic trained level. With the +5 to all starting stats that RT characters get over DH characters, that should about equal them out at rank 1.

I think it's helpful to think about the RT classes as positions on this ship (I understand that more options are given in ItS) so there's no reason your 'Arch militant' couldn't actually be a Guardsman from DH. A Scum would make a pretty good and sneaky Seneschal...