Porsche has a really good idea. A lot of people walk around with a Blackberry or phone case (or two) clipped to their belts. Build one that isn't a Blackberry case, but a holster. A perfect way to CCW...a fast draw combined with excellent concealment in office attire.
I would talk to somebody like Ken Null about it. This is precisely the sort of deep concealment stuff that he does. Set it up for a Seecamp, Rohrbaugh, or similar mini-gun.
And let me know. I want one, too.