Has anyone even cut a FRAM open recently? People throw that "FRAM filters suck" thing around so much, but I haven't seen anything CURRENT about them. For all we know, they're just fine these days, but because of ignorant interweb info-regurgitators, dated info might be getting spread around.
What I KNOW for certain is the Purolator PureOnes are great and that Wix/NAPA Golds are also great. Anything else good or bad I'm unsure of because people recirculate old info instead of keeping current.
Anyway, yes, there is a larger filter you can use. Whatever brand you buy, I highly encourage you to use a synthetic oil with that larger filter; you can push your oil change interval safely to at least 5000 miles if not 7-8k. Shell Rotella T6 0w-40, German (look for mention of Euro blend or "Made in Germany/Belgium" on the back) Castrol 0w-30, and Mobil 1 0w-40 are all great oil synthetic choices for the 4.0. Lots of insane research helped me arrive at that list. Really, the 4.0 isn't picky at all and could practically run on vegetable oil, but if you're going to buy oil, why not buy an ideal oil, right? Everyone has an opinion on oil, but at the very least, don't let somebody slam you with the myth that you need some specific oil because of the 4.0, its flat-tappet cam, and ZDDP (they much just call it zinc); it's a commonly-held misconception around here that we simply don't need to get into.
I have absolutely no insight into your parking brake situation, but for goofy, hard-to-find original typey parts, TeamCherokee.com is a common stop for me. Morris 4x4 (jeep4x4center.com) has also come through for me where other places haven't for some parts.