I'd like to see support for emulated dual drives (4040, 8050, etc) Right now I can't see a way to put a separate floppy image in both drive 0 and drive 1 of an emulated drive. It only allows mounting a disk image to a device number even though dual drives should allow two images to be mounted for each device number.
It's implemented a bit strange right now. You have to attach the disk image for drive 0 to device 8 and drive 1 to device 9. That's the reason device 9 is unavailable when a dual drive is device 8.