the recipie for a hide from desynthing the mantle is wrong. It does not cap at 24 anymore, if it ever did. First that would be a bit silly, as the synthing of the mantle caps at 27, and second, desynthing the ones i had made gave me skill ups all the way to 27 as well.
I'm a Samurai 46/Thief 23. So I have TH1, i get these things in a 1:2 ratio of killing Dhamels. Since noone is ever in the canyon, when the NM Dhamel, Sephorard or whatever his name is, I get to frag him too. Wortn 600-1000 on Midgrad Sormr.
I've been leveling in Tahrongi Canyon for a few days now. Among a party of three (without lotting), I've gotten roughly five hides an hour hunting Dhalmels. They spawn pretty quickly, so if you were actually farming hides, Tahrongi Canyon is a good spot.