Glad to help! My love for DBSK was rapid and truly scary. Yes, they do indeed have several drama series. I'm not sure where to download them from as I have been visiting the Greatness that is Youtube. The following link contain;

UNFORGETTABLE LOVE
UNINVITED GUEST
FINDING LOST TIME
DANGEROUS LOVE
TOKYO HOLIDAY

http://www.youtube.com/profile_videos?search_query=&user=jnie05&page=3

Dangerous Love happen to be a fan favourite. They have also appeared on one off episodes of different shows.

Also, their MV for the Korean version of 'O - Jung Ban Hab' is pure love. Actually, more often than not I prefer their Korean MVs over their Japanese MVs, but love their songs in Japanese. I'm not sure why.

If you need any more help just ask! Spreading DBSK love is a must now.

I blame perseid.