Expansion 2 slots and later on the Hitachi HD68HC000 10 MHz model is 4 slots. Then back down to 2 slots afterward. I guest 6 slots having loading issues so that why they drop back to 4 slots.
Looking at the Sharp X68000 - Games (TOSEC-v2007-08-22_CM) games list. There are some that have anywhere 5 to 9 Disk.
Here is example.
Superior Mahjongg PIV (1994)(Ving)(Disk 1 of 9)(System) Superior Mahjongg PIV (1994)(Ving)(Disk 2 of 9)(Data 1) Superior Mahjongg PIV (1994)(Ving)(Disk 3 of 9)(Data 2) Superior Mahjongg PIV (1994)(Ving)(Disk 4 of 9)(Data 3) Superior Mahjongg PIV (1994)(Ving)(Disk 5 of 9)(Data 4) Superior Mahjongg PIV (1994)(Ving)(Disk 6 of 9)(Data 5) Superior Mahjongg PIV (1994)(Ving)(Disk 7 of 9)(Data 6) Superior Mahjongg PIV (1994)(Ving)(Disk 8 of 9)(Data 7) Superior Mahjongg PIV (1994)(Ving)(Disk 9 of 9)(Data
Let me guest. Load System and then Data 1. Next Data 2 and so on. This how to load these? This is pretty weird because MESS I only saw 4 slots.