There are plenty of pieces of new equipment out there that use that size wheel and tire, especially rear tine tillers and snowblowers from Murray, Husqvarna, and Cub Cadet. The only catch is in knowing what uses that axle diameter, and the width of the axle journal is important also, unless you can compare off something the sizes of those two items are often never stated in the part description. (This is where a little research might be required if you want brand new rims). Finding the exact used rims on e-bay should't be too hard as mentioned, but finding ones that aren't all bent and rusty is the challenge as on L/G equipment the wheels often take a beating.
-Fordlords-