A guy in my wheeling club has a friend that has made a Cheromanche, I will see if he has a build thread on some forum. I might even see him today
He's an angel dressed in oilskins; he's a saint in the "Sou'wester,"
He's a pluck as they come, or ever can;
He's a hero born and bred, but it hasn't swelled his head,
For he's just the U.S. Government's hired man.
It's my opinion that it's more work than it's worth. The Cherokee is shorter than the Comanche as I recall, and it is a unibody vehicle. The roof is as structural as the rails below the floor. You can get away with cutting behind the C pillar and making a tiny little bed back there, but you'll be losing cargo capacity overall. Better, I say, to keep it intact, put the back seats down, and load it as such. I mean, it's not like you don't have space in the back already. The seats do stow. If you're not a fan of carpet in your cargo volume, go ahead and rip it out and bedline it. It'd wash out just as easy that way.
Don't get me wrong, I appreciate the want for a pickup, but the unibody design of the Cherokee is just not conducive to that. By the time you'd replaced the structural integrity you removed by cutting the roof off, you'd have lost all your cargo space again anyway.
1997 Grand Cherokee Orvis Edition
1998 Grand Cherokee 5.9 Limited
Go over to Pirate4x4. It's been done hundreds of times over. But yes, without reinforcing with the likes of a cage, it will be structurally weak. It may be more effort than it's worth, but tell that to the score of people who have done so in their wheeling rigs. I'm sure an adequate solution can be made for the X tube in the back.
"Chilton's and Haynes are for brake jobs, oil changes and starting campfires." - CJ7-Tim
'98 2dr/5spd Cherokee rockin' on tons, 5.9L V8 Magnum, HP60/14b, 5.13:1, locked, 14" coilovers, Dana 300 4:1 twin stick... oink oink!