the OP was from 2003, so hopefully their LP12 is sorted by now. would be a shame if not.
i have an Aro on my LP12 and it's great. however, folks have had good results with the Roksan Nima -- another unipivot design, but less costly. (the scuttlebutt is that Roksan modeled the Nima (anagram for Naim) after the Aro when Naim discontinued it.)
the Aro's a beautiful piece of engineering -- museum worthy, in my ever so humble opinion -- so well worth picking one up if you can find one. it just looks so slick on the LP12.