I like my 31's. IMO they are right in the zone of "it should have came this way" with the truck having a lot more capability than with the stock size tires but not ungodly tall for balance and to use day to day.
A 265/75/16" tire is technically 31.6" x 10.5"; a 235/85/16" tire is technically 31.7" x 9.25". However, usually I've seen the 235/85 tires only as an "E" rated tire, where the 265/75 tire can be found as a "D" rated tire. Might make a difference in ride the D vs. E rated tire. Otherwise they're about the same size as a 31" x 10.5" on a 15" rim (and often as a "C" rated tire).
And if you're lifting your ZJ and putting taller tires on it, you'll want to re-gear the axles. We went from the factory 3.55 (or was it 3.7-something?) to 4.10 gears with the 31" tires. The Dana 35 axle is weak (which is what you probably have), and the Dana 44A has limited gearing and traction device options (and has an aluminum center section). Swap out the whole rear axle with a new one made to your specs (we had a TrueTrac put in ours).
The Ford Explorer 8.8 is a popular swap for Jeeps too. A hair stronger than the strongest factory 9" and 95+ has factory disk brakes. Like a couple hundred bucks out the door geared as deep as 4.10 from the factory. You would have to weld on your own mounts (I did) but it isn't really rocket science.