Well buddy, 17x11's are readily available!
HOWEVER, I had to have my rear ones custom made for a 4 1/2" backspace, because I ORIGINALLY was gonna use the standard American Racing Torque Thrust 15x10 with 3.75" backspace, and I had my Strange S60 custom built for just those wheels, THEN when I decided to run 17's, a 17x10 with 3.75" backspace was non-existent, NOT A SINGLE SOUL made them...SO the only thing I could get without going to a 17x9, was stepping up to a 17x11, and to keep it centered under the car like my 15" wheel was, I had to increase the backspace 1/2" for the extra 1" wheel width on the 17"...
So, my rear 17's were expensive at $315 EACH...Plus a $230 Nitto 555 tire! So I spent about $1100 for my rear tire & wheel combo!!!!
I wonder how the deep backspace is gonna look on the car...Some people like it, some don't...