I'm not sure if you can do that PK? (acronyms for names too now too )
Seems like good logical thinking though m8, just don't think you'll be able to run the newer server as a BDC alongside the earlier PDC.
The minute we joined a W2K server to our network at work (NHS Hospital over 50 servers, and 1500 clients) it fought (and won!) for PDC rights.
It didn't seem to matter hoiw we configured it, the damn thing kept stealing the rights.
The previous PDC (NT4SP6) just gave up without much of a fight.
I doubt M$ would've taken a backwards step with regard to this issue.
I'd be inclined to follow the migration routine as prescribed by Enyo earlier.
It seems Windows likes the newest kid on the block to be the daddy.