I've been looking into possibly doing this on mine.
I've been looking at two types: I started off looking at butterfly valves, as they are widely available and have many options for installation. I would use a 6" valve on my truck, as my air intake goes from 6" down to 4", and it shouldn't have any flow restriction given the large down step. While they do have electric ones, I would probably try to make a mechanically actuated one that I could operate from the cab, as the electric ones are a large price jump and I would prefer mechanical for ease of use. Levers tend to be more durable and reliable.
The other valves I've been looking at and will probably go with is a brass piston valve or brass gate valve, as I can easily make a mechanical link up for them as well, and I can get them in NPT or combination NPT/flush mount. Probably still go with the 6", although I could probably get away with using a 4" on my post intercooler side if I really wanted to. Mounting a 6" against the top front fender would give me a straight shot on push/pull for the piston valve, and an under dash linkage would be the simplest version I've been able to come up with. It would also be relatively easy to cover and make even more inconspicuous.
As for my concern: the main reason I've looking into it is because I've just got through building a diesel engine for mine. For the amount of work and money I've put into that build, it would be a decent insurance. Overall cost would be about $4-450. The other reason is that I can make it a bit inconspicuous, and then I would have another "kill switch" that would be quite effective. If I'm going to be away on vacation I could remove a few cotter pins and linkage and it would probably baffle most would-be-theives or joy riders for quite a while.