I have thinking about making a Alpha Legion "fluff" army, that's based around them infiltrating imperial forces. I'm thinking to play with the space marines codex with an imperial guard detachment (so I get them as battle brothers).
"Design" vise I'm thinking that the Legionaers should be painted mostley as the space marine chapter they are impersonating, but with their real colors showing in chips and battle damage. Maybe some special squads like terminators with the real colour scheme. The guard units could have their aquila's/other symbols crossed out and like wise.
In game they will have a heavy focus on infiltration and such, so I'm thiking about using Kor' Sarro Khan as a HQ and whatever more I can think off. The guard will mostely be a infantry platoon, but maybe with a Valkyrie and Marbo of course.
What do you think? Ideas, suggestions?