[Hexiled Razz]

Which rear shock bolt? The uppers are studs. You should be removing one nut, not both. Loosen the other and the slotted bar pin on the shock mount will slide out. If these are giving you trouble, bend away at the tub of the jeep just above the frame so you can get a wrench in there. If it is the lower side you cant get off. Should be trying to loosen the nut, not the bolt. Never the bolt. Once the nut is loose, then you can use a pry bar and try and rotate the seized nut free. If neither works, cut the bolt head off, cut the nut off, use a pry bar to spread the lower shock mount a bit and run a hacksaw blade between the shock bushing and mount to cut more of the bolt so you can pry it out.

Rear TJ shock uppers are a traditional eyelet with a bar through them, fastened down to the frame's cross member with two bolts. If your rear uppers are studs, some serious redneck engineering/fabrication must have taken place.

To the OP; agreeing with ditching the JK shocks. No sense in doing several hours in work and hard labor to save 30, 50, or even 150 bucks. Even if the shocks were free, you'll have major suspension geometry problems with them installed.

With that being said, if you truly want to continue with the JK shocks, here's what i did.
-unbolt all the body bolts, leave the side of the shock you are NOT dealing with loose, but not completely unbolted.
-Jack up the side of the body with the shock you are dealing with. This gave me enough room to get my dremel in there with my 90 degree attachment and a fiberglass reinforced cut-off wheel. It made short work of the nut/bolt.(I would put water-soaked rags on the gas tank though just for safety) Then, you just use a normal nut and bolt when you put in the new shock.
-Repeat for the other side.

It takes a lot of work but this is the easiest method i can think of if you lack the torches/drill bits/drill to do it from the bottom.