Element,
Check out
CraziesCash, they have only one site and that's
AllOver30.
Members area is very clean and easy to navigate, they have great content, regular updates and an excellent webmaster support. They do have "9 to 5 ladies" which is pretty much a secretary theme. They have Fetish, Lingerie, Housewives, Hardcore, Lesbian, Outdoors....
They do convert well
Also check out
OldDollars for
OWAMW. They have plenty of promo materials as well. Their content includes, milfs, housewives and older ladies.
What I like about them is, when it comes to mature niche, these guys know what they're doing