I am runnning Cragar SS 17X8's with 245/45/17 all the way around.
Thats a 25.7" tall tire with 4.10 gears its killing me on the highway. Id like to get a taller/wider tire under it, and get that staggered look. but all the tires I see are SUV truck tires with a real knobby tread, which would look pretty dumb on my car. I was looking for a 255/60/17 for the rear. My question is Has anyone run into this problem and what size rears are they running.

You could try 255/55/17 tires, which are the stock size for my Dakota R/T and are a car tire tread instead of knobby. Just a thought.

The biggest I found so far was a 275/40/17 that I am running on the rear my Elco.

Here are a few choices for you:
285-40-17
http://www.tirerack.com/tires/Compare1.jsp?width=285%2F&ratio=40&diameter=17&skipOver=true&y=11&ratio=40&skipOver=true&width=285%2F&diameter=17&x=27&startIndex=0&search=true&pagelen=20&pagenum=1&pagemark=1&RunFlat=All
275-55-17
http://www.tirerack.com/tires/Compare1.jsp?width=275%2F&ratio=55&diameter=17&skipOver=true&y=10&ratio=55&skipOver=true&width=275%2F&diameter=17&x=12&startIndex=0&search=true&pagelen=20&pagenum=1&pagemark=1&RunFlat=All
255-60-17
http://www.tirerack.com/tires/Compare1.jsp?width=255%2F&ratio=60&diameter=17&skipOver=true&y=4&ratio=60&skipOver=true&width=255%2F&diameter=17&x=19&startIndex=0&search=true&pagelen=20&pagenum=1&pagemark=1&RunFlat=All
275-60-17
http://www.tirerack.com/tires/Compare1.jsp?width=275%2F&ratio=60&diameter=17&skipOver=true&y=12&ratio=60&skipOver=true&width=275%2F&diameter=17&x=12&startIndex=0&search=true&pagelen=20&pagenum=1&pagemark=1&RunFlat=All