A post at the OSXAudio forums suggests an update to DP should be at MOTU's site on Friday - however I'll assume it's for version 4.5.x and not 4.1.x.
Updated MOTU hardware (PCI & FireWire) drivers have already been released this week, so I think they're more on the ball with Tiger than with Panther.
I'm in the same boat (have 4.12), but will splurge for 4.5x if the initial bleeding edge upgrader comments are positive.