There was actually a GREAT deal of Highlander Slash. Also Anime is the most popular forum of slash since they look all femme at times anyway.

Popular: Gundam, Dragon Ball, Ronin Warriors, Weiss Kreuz

At least thats what I read. ^_^

And yes LotR was very popular with elf fucking. Gotta fuck the elf. My favorite by far was Legloas/Haldir. Two prissy blondes getting their rocks off. Nice S/M story.