While Scout axles could be modified with new brackets and made to work for your TJ, that wouldn't be an easy or inexpensive way to go.
First, your front Dana 30 is fine for up to 35" tires. That's not to say it is stronger than the rear Dana 35c axle, it's not, but it is only used in 4x4 and only sees at max 50% of the torque & stress that the rear axle has to be able to withstand.
For most people, so long as you don't also install a rear locker (bad for a stock Dana 35c), the Dana 35c holds up to about the 33" tire size, within reason of course which means you're not hammering it offroad. So unlocked, I wouldn't give it much worry.
If you did start doing tougher trails, there are several very respected upgrades available for the Dana 35c axle from Superior Axle. One is their Super 35 kit which provides beefed up alloy 30 spline axle shafts to replace the non-alloy 27 spline factory shafts, plus it includes your choice of several lockers. The other choice is their "C-Clip Eliminator" kit which does several things to improve the overall strength, including alloy chromolly 27 spline axle shafts. I know of some pretty hard wheelers that have tried to break even their c-clip eliminator kits, let alone the far beefier Super 35 kit, but so far their axles are doing fine on 35" tires. Your axle should be fine as is on 33" tire but realize that should you need to beef it up for whatever reason, that you have several choices of very good ways to go with it.