Ian Scott did create the PicoGUS card emulating the Gravis Ultra Sound sound card (you can buy a PicoGUS in Europe at Serdashop).

He has announced today the future availability of the PicoIDE which features ATAPI optical disc emulation and IDE hard drive emulation. A new card next to the PicoMEM card by Freddy Vetele (the PicoMEM can be bought too at Serdashop).

Even for PC XT (and up), it can be interesting to use SCSI emulation as it exists SCSCI controllers for PC XT : BlueSCSI v2, ZuluSCSI, PiSCSCI.