A trip to lowes and about 15 bucks later, this is what I did to mount my Hi-lift to my tuffy security enclosure. It's very sturdy. I might flip the bolts around so the nut is inside the enclosure. That would give me a lot more security... But would be a pain when I needed to access the jack.
I'm probably going to...the only downside is having the nut and bolt sticking down in my trunk area. That and it'll be a pain in the *** to get the hi-lift off when I need it, but its better than being stolen.
When you lock the Jeep with the key-fob you start a timer. I cant remember what it is...like 30 seconds, where you can reach in and hit the unlock button. When that time is up, the unlock buttons don't work anymore and you have to either use the key itself or the key-fob. It wouldn't stop someone from getting the door open using the physical unlock on the door, but they wouldn't be able to get the tailgate open without the key.
The high lift brand mounts are cheap enough. They have the wing nut for easy opening. Plus the bolt has a hole in it for a lock so you can't remove it. Think that would work well on the trunk lid ... If you're worried about locking it down still.