Well, some of these niche ones are relatively new and aren't as fleshed out as I want them to be yet --- like missing banners and more sidebar site links, but others have been up for years. This isn't all of my blogs, but gives you a general idea of the niches:

http://cumonboyz.com/

http://tightiewhitieboys.com/

http://tattoogay.com/

http://cravebears.com/

http://www.twinklads.com/

http://seniorcocks.com

http://gayasianteensex.com/

http://gaymeninsuits.com/

http://www.juststraightcocks.com/

http://gaysubmission.com/

http://pantymeat.com

http://footfetishgay.com/

http://soldierseduction.com/

http://straightboynaked.com/

and a whole bunch more in various gay, straight, bi and tranny niches.

For uncut I still need to setup and develop HoodedHunks and UncutBlackBoys