There has been lots of discussion about this on the JK forum. Here is a link for the thread on Tire Sizes .... You may find interesting and informative.
Largest tire on stock JK? Here's your answer!
For 17" inch wheels there are a couple manufactures building these...
And others who offer the correct offset and back spacing for your Jeeps.....
There is also a Thread or two on the JK forum about "The COMBO" ,
I suggest you read thru those threads too. They deal with tire / wheel size that fits with out going to Spacers and lift kits..... Have Fun !! "BH"