The StrongARM is a 32-bit processor with a legacy 26-bit mode which RISC OS 4 uses.
So you could theoretically run Select32 on a RiscPC. Most likely the 32-bit version of Select, once merged with RO5, would implement RO5's HAL (how else would it run on the Iyonix?) so if ROL decided to make a compatible layer for Select32 to run on IOMD/VIDC in the RiscPC then it would run.
But then you have to ask yourself, why would you want a 32-bit OS on the RiscPC, particularly if it provides no extra features over Select26? As on Iyonix, 26-bit software would break and have to be run under an emulator such as Aemulor. The RiscPC is simply too old and slow to make this feasible.
I agree about the rather limited scope of the survey though - surely the Merlin wishlist is enough for ROL to realise that there is demand, but most of their potential customers are still just potential customers so there's no use asking only existing customers what the potential customers would like!