new drive shafts will be needed.
12.5" wide tire on a stock rim will work but you may not want to air down much. might slip the tire off the bead. you will need wheel spacers though.
I'm gonna disagree with just about everything he just posted.
new shafts are not needed with an unlimited on that much lift.
you may wear your stockers out a little faster so figure you have about 15-20k miles to get some new ones.
I've been lifted since the week I bought my Jeep, so 40K miles over 2+ years.
I'm still running stock shafts with ~6" of lift
I detonated a front rzeppa joint on one but I was running about 7.5" when I did. I replaced it with another stocker I got cheap off ebay.
New shafts are on my eventually list.
as far as the stock rims with 35x12.50s, I dunno why they would slip a bead easier than a wider wheel, the thinner wheel actually puts more pressure on the bead. I've run 35x12.50 mud grapplers on my stock rims for a year and a half and ~25K miles with more than a little off roading with no problems
The one part I DO agree with, is you will need 1.5" wheel spacers to clear the wider tires.
Look for something hubcentric, spidertrax have a great reputation and have worked fine for me since the 2nd week I brought my rig home.