This question was asked (in long form) in the Adult section of the official Second Life forum.
Are there blogs reviewing Second Life adult products and places?
I don't know yet if there is a one-stop niche shop, but I did ask the OP if she'd seen any of these sites:
Link to the original post: http://community.secondlife.com/t5/General-Discussion/A-Proper-News-amp-Information-Site-for-Serious-Adult-Play/td-p/1480359
Related post link: http://community.secondlife.com/t5/General-Discussion/Is-there-a-blogging-circle-I-can-add-my-blog-to/m-p/1324783