I just wonder why you guy worry so much carry gun case or bag to public transportation. I never got any problem with the cops at all. As long as you didn't take out your gun in public then it's done.
I usually carry my gun bag on my back take the bus go to the game at local paint ball field and usually take the Metro with the cops as well, none of them never ask me what inside the bag. So no worry at all.
For the gun, I recommend the 9.1.1 tactical, I had one and it's never disappoint me since I got it.
Also the hard gun case, I would recommend something like that.
or if you have cash to burn then get a pelican case.