Here's an update. I called the van conversion shop today, and the rep says it would cost about $325 to have 2 of the "hockey puck" style locks installed for both the rear doors and middle doors (includes parts and labor). Seems like a reasonable cost to me, especially because I know this place will do a first rate job. I certainly wouldn't try do to this myself, haha! Unfortunately, this same shop doesn't do the sliding deadbolt locking design. That's too bad, as the sliding deadbolt design with its built-in lock/key seems more convenient, versus the hockey puck lock that needs to be physically taken out and re-inserted for locking and unlocking. Oh well. Anyway, I ordered 2 of these hockey puck locks with matching keys, and will have this installed probably next week. Geez, yet another set of keys to maintain! I just got more keys to add to my collection recently when I installed new wheels with lug nut lock keys. You should see all the many keys I have on my multiple keyrings, it's pretty sick! I have everything locked down on my van. Even my electronic Viper alarms have alarm backups! I'm now looking to add multiple *physical* security locks to complement the electronic alarm locks. All of this would deter the casual thieves when they see the multiple security locks and backups installed. Heck, I even have "The Club" lock on my steering wheel too, hyuck, hyuck!