Depending on how you want to go, it's possible to get to the top of one tree and still take several first tier abilities from the other two trees. My Jugg for instance is 35/2/4 (this
, if you are interested in specifics). And if you want to sacrifice the top of tree talent, you can go even more extreme, becoming something of a hybrid like you described earlier. That's what I am planning with my Sorcerer
(although I am extremely annoyed in that case that I want to be Lightning spec'd, but half the lightning abilities are in the Madness tree).