I've seen three kilts aside from my own in Columbus that weren't on pipers, and two don't really count based on the setting they were in.

The first was a gentleman wearing a camo Utilikilt at a Columbus Crew game. I complimented him on it and he said thanks (I didn't have one at the time).

The other two were at a pre-St. Patrick's Day party at Fado Irish Pub - it was the St. Baldrick's head-shaving party. One was an olive drab Utilikilt and one was a Stewart Royal tartan with the full regalia - Glengarry, Prince Charlie jacket, and the works. I was there in my khaki Utilikilt at the time, so there were three of us total. But those are the two I don't count, since it was a St. Pat's type thing.