Tom Harte has released an update for his ClockSignal multi-platform Emulator for Mac OS. The latest update resolves an issue which was preventing both the Apple IIe and the Enhanced Apple IIe emulations from detecting an attached floppy disk drive.
Other platforms that the Clock Signal Emulator contains currently are:
Apple II/II+ and IIe;
Commodore Amiga (not 100% accurate yet)
Commodore Vic-20 (and Commodore 1540/1);
Macintosh 512ke and Plus;
Sega Master System;
Sinclair ZX80/81; and
Sinclair ZX Spectrum.
You can download the latest version of the ClockSignal Emulator from the Github page at: