Well, I got my MPC2000XL tonight. Of course, the first thing I do is open it up. I took a quick pic.
Turns out there is an internal SCSI connection AND an internal IDE connection.
I also confirmed my earlier suspicions that the XL uses the same SMPTE chip from the 2k model. I just removed the chip from the old option socket and inserted in the XL's already built in socket. There was even a marking on the board for the same chip number. I was also able to easily install the8-out expansion and the EB16 effects board (which used to be in my otherMPC2k).
The machine boots without a floppy. There's a flash ROM in there. There's a couple of jumpers on the MB that concern booting. There's also a couple of empty IC sockets. One is for a Boot EEPROM (but not needed since has a Flash ROM).
As far as construction, I really don't feel the case to be any weaker than the original. The machine itself seems weigh slightly more. The SCSI connection appears to be more solidly mounted now. I was always afraid I may break off the old one sometimes. I don't feel that way with this one. I would have supported the motherboard in a few more places. When I was inserting cables and such, I had to support the motherboard every time since it would flex if I didn't and it wasn't easy to get around everything to do this.