If you never have any drips of oil it is likely that you are burning it. Passing the emissions isn't the best indicator of whether you have a problem or not. It does sound like you have a rear main seal problem, but that doesn't account for the amount of oil you are using.
Few things to recommend here.
1. Take a look in the air cleaner box. Is there any oil on your air filter or in the bottom of the box? If there is, you should replace all of the CCV (crankcase ventilation) components. Two hoses and two grommets. About $45 aftermarket or at a dealer.
2. Pull all of your plugs. You can tell a LOT by how the plugs look. Take pics and post them if you want comment. Look for oil fouling.
3. A compression test is never a bad idea here. It is a good "snapshot in time" of the internal condition of the engine.
Good luck and keep us posted!
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!