When reading your post I was afraid that you were going to ask to add PPG support in one or another way
It is NOT possible to create or read 5.25 floppy disks for the EII. Not with a PC, nor with a Mac.
None of the specialized diskcopy tools and drivers support this, because the required hardware (controller) is simply not available in PCs and Macs. EII uses a non standard (non BIOS compliant) way of controlling its floppy drives. Some old Unix machines (or maybe even old Apples) from the early eighties supported this floppy format. Digidesign and Emu owned some of these machines to transfer disks to computer. When converting your OMI CD roms I noticed by the way that OMI must have had this possibility too, since their first volume seems to contain full floppy disk images instead of "just" memory dumps of the EII.
Anyway there may be a small possibility that using a specialized floppy controller in the PC instead of the default one can do the job. But there are only a few providers of such devices and they will have to custom-configure their chips in order to support the EII. As far as I know someone on the yahoo board was going to try this.
But if I were you I would forget about this wish.
Adapting software to support EII ? One would need the source code and understand it, right
So I wouldn't rely on this dream either...
Just FYI right now I'm investigating the possibility to use a PC instead of an old Mac to use the RS422 interface of the EII. I have the required hardware here (cables, RS422<->USB converters, ...) and also rough information on the communication protocol but until now my experiments were unsuccessful. Probably a problem with the voltage level or clocking differences between the EII interface and the standard RS422 ports (the Mac port was not 100% RS422 compliant and Emu relied on the Mac specs).
I need digital scopes and logic analyzers now to proceed but I don't have this equipment and I won't buy it either (too expensive).
The more interesting result of this experiment would be that I will also be able to let EMXP communicate with the RS422 on the Emax-I, making it possible to load/unload complete soundbanks to/from the Emax (no software, even old Mac software, is supporting this until now).
As you see, there are still quite a lot of challenges out there in Emu world.
I'm still doubting whether I will add SoundFont2 support to EMXP or not. The idea behind this was that it would "open" the Emu sample banks to any other sampler out there (and vice versa) since SoundFont2 is a widely supported soundformat. But I have a slight feeling that no one is really interested in this feature... SoundFont2 is a very generic dataformat which means it's quite complicated to support. It would take a huge amount of time to extend EMXP with SF2, so I won't do it if it's not useful or not high priority.
Any other suggestions for additional features in EMXP are welcome of course ! But don't ask for a graphical user interface.