The Psion 3 series used 8086 processors, so they could have released a standalone version of SIBO for IBM-PCs with relative ease.
In fact, Psion did release a SIBO "emulator"* for DOS which seems to be basically a PC port. It's intended for developers, and hews to replicating the mobile devices rather than taking advantage of the PC hardware, but you can imagine polishing it a step further.
In fact, Psion did release a SIBO "emulator"* for DOS which seems to be basically a PC port. It's intended for developers, and hews to replicating the mobile devices rather than taking advantage of the PC hardware, but you can imagine polishing it a step further.
* https://home.hccnet.nl/joop.nijenhuis/psion/emul_0e.htm