Yes, Asus has the Z71V, which is also used by VoodooPC, ABS, Winbook, and other boutique shops. I know a few from Acer does, too. Don't know if anyone else has them though. Probably Sagers...
1. Yes
2. Yes
3. I would say yes, it would be unlikely they'd switch- if they did, they'd probably have a non-native SATA adapter. As for Modular bay option, it may bottle neck, but not as much- just a hair off of direct connection. Nothing to worry about since it's not the main drive.
just was wondering, a lot of desktops that have sata have pata also usually implemented as the cd / dvd drives, though it is like they are affraid to go to just sata, most mainboards have sata + primary and secondary Pata.
I know that there is not room for that in a notebook.