No need to purchase an overpriced floppy drive from Akai. A regular PC floppy will work inside the MPC 2000.
The only caveat is the location of the power connector on the floppy as many of the power cables inside the MPC 2000 and MPC 2000XLs are too short for some drives.
I've used a Sony MPF920-F and TEAC FD-235HF. What model floppy drive is inside your MPC 2000 currently?