Al - because I like you so much (not because I am argumentative
) I agree with Jared... I looked into this for re-inflation of tires after 4x4 oversand escapades on the bayside beaches. They're not like the backside where you can inflate at the parking lot - in fact Quivett requires a very long ride over potholes and stones before running to the nearest gas station over a mile past the rutty road.
I talked to scuba shops on the topic and although they seemed up on the idea, the things they said about inflation and safety measures turned me off.
According to them you can only fill at a dive shop, and the tank must be tested regularly for integrity in the concrete test tank. He said a tank is effectively "an air bomb" and "if one blows in the test tank, everyone in the shop knows it". He said it would not be a great idea to leave it in my truck between trips and to watch temperature extremes.
Despite this the tanks are capable of incredible filling power, unlike the tire tanks which I heard can't re-fill all four of my tires from 15 psi. I would probably need two tire tanks, where the scuba would cover multiple trips.
After this evaluation I decided to look into portable gas compressors and concluded that two tire cans is the way I will probably go if I decide to buy Oversand permits for anywhere besides the backside or the Race.