How many 2000xl versions are there?

Does anyone know how many different variations of xl's did Akai release?

ie SE1,2,3
Xl w/floppy, zip
Blue MCD
Also is there a difference between the Xls with light gray trigger pad and black trigger pads? different text fonts? etc.

You pretty much got all of them. The blue one didn't originally have the memory card reader, it was the same as the beige one... just like the SE models. Then the MCD was launched as a new product. In reality every single MPC is the same exact thing, some just have different options.

The originals used to come in regular, studio (+smpte, 8 outs), and studio plus (+fx). Only difference on the front was a sticker.

Only difference between the black pads is that they look cooler from far away but they get dusty real easily.