I've also been obsessing. But I'm not sure if I'd rather have a faster chipset with Montevina or have that plus a case redesign.
The upside of an upgrade is having the latest and the greatest if there is a case redesign. It will be very nice and will look and probably be amazing. The downside is, as a Rev A, it will probably be incredibly buggy.
Depending on exactly what it is, I may step down for a cheaper, less buggy, more complete plastic MB. Plus, with plastic, you get a much greater wifi reception. Which is handy when you have to leach it for free from the college you live right next to or the club house hopefully your room is close too.
Just have to wait and see what happens.
I think they fixed the wifi issue with by changing the frames to have a little plastic corner like the iPod Touch. Look at the released casings for the Macbook Pro, you'll see it in the upper left hand corner of the bottom piece.