Never heard Ermz's own experience with Ultrasone >.> I don't work for them, I swear. I would kill to own ANYTHING better than my current headphones, but if he's looking to balance bass, they seem like the logical phones to go to. Pick up some PRO900s (or the 2900 for open back) and give us your thoughts! The midrange I've heard is recessed unless it mates well with the amp, but it can be brought up by putting some self-adhesive felt over some of the holes under the outer grille.
Or the PROline 650. Checked frequency response graphs, and compared to the ATH M50 it's incredibly similar. The dip in the lows is around an octave lower, but... :shrug: The graph doesn't tell all. Would be worth a shot though, I think. While that model is discontinued, I think the PRO750 is what replaced it, and is essentially similar