Hoosier makes a 245 and a 275 in 15" diameters. These may be a good choice for those running 8s and 10s on a narrow body car.
If anyone wants to try the Hoosier R6s without splurging for a new set, JB Racing Tires has used ones for $50-80.
I've used them before when experimenting with unfamiliar tires.
Jb Racing Tires
John & Mike
4985 Hwy 50
Delavan WI 53115