True the Iyonix isn't 100% compatible with 26bit software but Aemulor goes a long way to solving that problem (most if not all of my 26bit software works on the Iyonix under Aemulor) What software do you use that works under 3.7 but not RO 4 ?
Not sure I'd want to see an Iyonix with an 8 slot backplane (asking for timing problems there ) the Podule interface is so sloooow.
I agree that the audio output on the RISC PC is better than that on the Iyonix (at the moment), but the RISC PC doesn't include audio inputs (4 on the Iyonix)
Regarding USB - yes the RISC PC can support it but its strangled by the slow podule bus, where as the Iyonix supports USB2 !
The A9 can't nativley run 26bit software either, can't use podules (or PCI) runs USB1 (although much quicker than on the RISC PC I'm sure) And Isn't that much cheaper than the Iyonix.
So all the reasons you have given for not wanting an Iyonix also apply to the A9Home.