Truck cap with rear "walk-in" door - security

[therealdgh]

Anyone have one of those truck caps with the "walk-in" door on the back? The walk-in door is the one where you would remove the tailgate to put the cap on because the rear door comes all the way down to the bed floor.

The ones I have found so far are:
A.R.E. CX or MX series CX Series Truck Caps : A.R.E. : Manufacturer of fiberglass pick-up truck caps, tops, toppers, camper shells, canopies, hard tonneau covers, work caps and truck accessories.
Unicover Caps Safari II or Safari II X-tra Truck caps - Unicover fiberglass safari II caps

I am looking at one of these because the tailgate was stolen before I bought the truck and I have four girls and two dogs. (The dogs and girls won't all fit in the rear seat.) I want the dogs to be able to jump in and out of the bed when I open the door without me having to pick them up - with the three foot drop, they still might not, but I can try.

How is the security on those rear doors? Has anyone that has one had/seen a break-in or attempted break-in? Are they easy to jimmy?