For about $50 each you could go to Summit or Jegs and buy some Bart's steel wheels which are designed for Nascar but will do a nice job of mounting your drag slicks as well, all with being pretty light in the bargain. They've got all kinds of backspacing and width options.
Plus, 1/2 an inch short on your current wheels is hardly an issue preventing you from mounting tires. They'll just protrude a tiny bit more from the wheel edge. I have 10.5" wide 26" BFG drag radials mounted on 7.5" '01 Mustang cast wheels and they sit flat on the road just fine. I'm replacing them with 16"X10" wide bias Hoosiers before this season gets going.
2014 Premium GT, SGM, Brembo, Auto, Tech, Comfort, etc. GT500s, Steeda UCA, VMP auto tune, 100 shot on BBR tune, best et: 11.38 at 120.85
2012 GT, Candy Red, Brembo, 3.73, Tech, Comfort, etc. Procal tune, Roush upper, UMI LCAs, Steeda red bracket, GT500s, 28X10X16 Hoosier slicks, best et: 11.91 at 115.23 RIP