There are some companies making a 7R X 15 (the radial replacement for the old 7.00 X 15 bias ply), but most people are using the 225/75 X 15 ST tire. However, lots of people are having troubles with the newer "ST" tires. Yokohama is one that I know makes the 7R X 15 tire in a load range D.
"Those who expect to reap the blessings of freedom, like men, must undergo the fatigue of supporting it." Thomas Paine
'08 34' Classic SO, '12 Ram 2500 4X4, 6.7L Cummins.