You could also look for a pounce wheel. It's a tool used in sewing, for example, to transfer the lines of a paper pattern to a piece of cloth. Some modelers use those for riveting. There are different diameters, of course, and you'll want to see what matches the pattern you're trying to reproduce.
I've even seen a modeler who made his own with gears from some old watches.
But if you extend your search to pounce wheels, you might find a tool that does with the model companies' products do, but at a more reasonable price.