I understand the desire for discreet carry of a rifle, but aside from those in the shooting community, I doubt many would take a 2nd look or thought about many of these cases as long as they weren't covered in pouches and/or Molle straps. There is a lot of cross over now with shooting/tactical gear being used mainstream all made out of Cordura and using MIL/tactical colors. I see Maxpedition gear being used for baby bags, hell most companies make brief cases and such now. I have been using aFoliage Maxpedition Methuselah daily for over a year now and the only person that has ever said anything about it was my wife when I first got it who immediately thought I bought another gun bag.
Again, I think that the people that are not into shooting really have no clue. Vendor bags, popup display cases for sales, and stuff like that all "look" like rifle cases, but no one gives them a second look. My office has 1/2 a dozen of these, and (trust me) an AR fits perfectly in them. I have carried these bags in business atire, as well as unshaven wearing jeans and t-shirt, through airports, hotels, resorts etc and never had anyone give me much of a 2nd look, and never question me etc. All these covert cases are fine but at $100-$150, there are fine alternatives out there, get creative.