It's not CP/M 3, but it is possible to port CP/M 2.2 to banked-RAM systems and get a 61+kB TPA. I've done this for the NC200. The BIOS bank manually...
This is my immediate problem too, I have both a GW and FE but can't find a 40 track drive. Well, unless I dismantle either my RML380Z or TRS80 Model...
Unless a machine, like the Tandys, specifically call for removing the disks, it's generally better practice to leave a disk or one of those cardboard...