Rob: since Select is softloading anyway, there is no need for it to go "on the metal" at all - just like the Linux port available, RISC OS 5 will have set up everything nicely. Apart from that, the IYONIX does not use "magic hardware" anywhere, just bog-standard stuff.
It is of course not sensible to replace the whole RISC OS 5 stuff with the typical "Select softloading mechanism" which just replaces the whole OS. You'd have to reinvent a lot of stuff that works just fine (USB drivers, nVidia drivers, IDE/ATAPI stuff). I guess the way much of the Select extensions were done is pretty much incompatible with the idea of softloading only a few parts of it over another RISC OS version. Which is just too bad for RISCOS Ltd. in the current situation.
Anyway, there is still a lot of Select stuff which should be portable in a modular way to extend RISC OS 5 with minimal changes - the whole ImageFile* architecture and with it !Paint, the thumbnailing filer, CDFS, networking stack, alpha channel and CMYK sprites... problematic things would surely include the window manager changes (round buttons) and perhaps the system-wide cut&paste&drag of textfield content.
I am quite sure that the money from 130 additional Select subscribers would be more than enough for the work needed to provide such an "IYONIX Select". So we end up with the same conclusion as always: RO Ltd. could do it, but they don't want to do it. For whatever reasons.