yeah, they are used quite frequently. i thought it was mostly for yaoi, since, you know, there are more yaoi couples than hetero.
and hahah, i know all of them. i mean. all. like i can tell you off the top of my head that chikusa is 49 and shamal is 30. i mean, not that they're used much or anything... but just in case a 1449 is written or anything, i'll know to stay away.