Check the Evolved Undead template, in Libris Mortis. It has fast healing 3, plus a bunch of other really nice goodies, and it's only worth +1 LA.
Maybe you could have a 'troll template' that has +4 Str, +2 Con, -2 Int, and -2 Cha, Large size, and fast healing (and the giant type), and leave it at that for +1 LA. Could work.