It could be argued that sexual predilections, such as fetishes, BDSM interest and paraphilias are not a choice (although we do choose to actively pursue them). In this sense, BDSM or kink would also classify as an alternative sexuality (not merely an alternative lifestyle, which denotes a choice).
There has been some chatter (on the interwebz) about having kink and fetishism classified as an orientation. Galen Fous, for example, calls if Fetishsexuality and Dr Michael Aaron includes Alternative Lifestyles in his AltSex NYC conference. Many of the researchers, therapists and sexologists I have spoken with for Stereo-Typed do not make a distinction between Alternative Sexuality and Alternative Lifestyle.