If you're looking for 720p then maybe you can try this torrent site, key in the drama titles. As for older dramas, I'm not so sure whether there are still people seeding though.
http://www.nyaa.se/?page=search&cats=5_0&filter=0&term=

For direct dl links, can try this forum (just register and you're good). Search in their respective threads, there'll be links for both 480p and 720p. Movies can be found in this subthread too.
Other sites of interest:
jdramacity - offers 480p files (normal quality)