It isn’t so unusual for VKei bands to provide OST for doramas. I just find it interesting that most of the times it comes from bands that aren’t signed to major labels. As I mentioned above, a shitload of bands provided OST for the Kamen Rider series over the years and I remember chariots once provided OST for some radio dorama, I think. Couldn’t find info about it online, but I remember it being announced back in the day.
In 2009 THE KIDDIE provided OST for the Shopping Program, ポシュレデパート深夜店 (Poshlet Depaato Shinyamise) during the month of October. Their song ‘BLACK SIDE’ was also used as the Ending Theme to the show, 小熊のベア部屋 (Goguma no Bear Heya) during the month of November.
Kagrra released a maxi-single with 3 OSTs. Two for doramas and 1 for a movie. I also have some faint memories of Kagrra, getting their own dorama and Kaya writing some chronicles that were adapted into an audio dorama for some online radio show or something like that. Not sure about that, tough.
This reminds me that 10 years ago Jinkaku Radio were supposed to provide the ending theme for an anime called Daily Lives of High School Boys, but their vocalist talked shit about one of its voice actresses and it got cancelled, LOL. They disbanded soon after that.
Also, Versailles got their own tacky-ass dorama. It’s awful, but at least they don’t take themselves too seriously: