Has anyone found a lockable vehicle mount that allows for a aftermarket front rail system, top-mounted sight and vertical foregrip? I have looked at Big Sky which I know makes good mounts, but they all lock over the standard forearm piece.

OK, based on the dead silence, I'll guess that no one has any ideas. I am thinking of having Kalispel case make me a custom lock box. http://www.kalispelcaseline.com Has anyone had any experience with them or their products?

Quoted: I am thinking of having Kalispel case make me a custom lock box. http://www.kalispelcaseline.com Has anyone had any experience with them or their products?

I have a black powdercoated Kalispel breakdown 38"X14" shotgun case I keep my 24" Varminter (broken down) in.  
This case is easily the toughest case on the market, superb quality, you will not be dissapointed in any of their products.
I'm even considering a custom black powdercoated  pistol case (haven't yet measured but about 26'X14") for my 14.5"/Phantom or 16" Dissipator/Birdcage carbines.