You guys checked out the latest Street Radial tires from Mickey Thompson? I put some on my van's 18" wheels but they offer several "sensible" sizes for 15" wheels too. Here's a link:
a 275/50R15 would be a 26" tall tire, about 11" wide. so a 26" x 10" or x 12" on a 15" wheels would work in Mickey T's. The tread pattern looks great too! Good luck