You'll need a 17x9 in the back for a 275. Smallest recommended rim for a 275/40/17 is 9", so you won't find many tire shops that will squeeze it onto a 17x8". Plus, you wouldn't want to, as it will create a lot of sidewall bulge that will hurt handling.
For rim size and backspace, I'd run a 17x9 with a 5" backspace in the rear and a 17x8 with at least 4.5" backspace up front. In the front any backspace from 4.5" to 5" should work just fine. You don't want to go more than 5" because of the possibility of tie rod interference.
For tires, you'd be looking at 245/45/17's and 275/40/17's. It would be nice to run 275/45/17's out back for a little more tire height, but they just don't make them anymore.
With that set up everything should fit pretty well. The front with 17x8's, 4.5" to 5" of backspace, and 245/45/17's should be well clear of everything. In the back with a 17x9", 5" of backspace, and a 275/40/17 you should be ok. It will be tight with the stock spring location, but it should work on most cars without any problems.
I have 275/40/17's on 17x9's with a 5" backspace on all 4 corners of my Challenger. I had to roll the passenger side fender lip and run some negative camber up front, and in the back I'm WAY clear with a B body rear and 1" spring offset. You might also look into Summit's Legend 5 series rims, they have the same 5 spoke design and are available in all of the sizes you would need. They're also on sale until "cyber Monday" if you're ready to pull the trigger now. That's what I have on my Challenger.
http://www.summitracing.com/parts/sum-141-7865gm0/overview/http://www.summitracing.com/parts/sum-141-7965gm0/overview/