Maybe in your area there aren't, but there are many places that have regular events.
the same facility that I use to autocross holds autocrosses for the BMW club, Porsche club, SCCA, and on the weekends they're not doing anything, there is a drift event there.
http://dailydrifter.com/ look at the schedule- they hold events at minimum once a month.
that's all at Gulf Greyhound park on the SE side of Houston..
on the North side, Houston Motorsports park holds regularly scheduled competitions..
Texas A&M also has a group of ricer--errrr, 'drifters' that do several events a month in that area as well.
I also know of a car club in Tulsa, OK and several groups in Dallas that hold these events on a regular basis as well.
and this is in the midwest where imports aren't exactly that popular. you go to the drag strip on a friday night and you may see 10 imports there, as opposed to 100+ domestics. You're in Nashville, I'm sure you can relate. so just imagine what other places look like that aren't filled with country singing rednecks.