I believe this performance was a one-off for the concert, as they did different solo stages for their next concert, including one where Sungjong was in drag (http://www.youtube.com/watch?v=H956cYGCt6k). (Sungjong is usually perceived as "the girly one", "prettier than a girl", etc., so part of him playing Hyunseung was as a conscious effort to "show his masculine side".) There's a bunch of "Trouble Maker" cover stages floating around on Youtube - IU did one recently - but the only other same-sex pairing I can think of is when Hyunseung himself reprised it at a recent Beast concert with Dongwoon covering for Hyuna, in cutesy drag, i.e., JOKE:


There's also the role of fanservice to consider, where part of the enjoyment is from the fantasy that Sungyeol and Sungjong are or could be a couple. I'm not sure how that plays into making their performance more or less enjoyable than the original, though.