Under the FAA system you can take someone who to sit RHS whilst you conduct a practice ILS under the hood, they should hold a PPL and be rated on aircraft type (i.e. multi, etc!). They maintain a lookout for you for conflicting traffic. Obviously the fact they can see the runway and will know if you are way off course would enable them to call a halt if they think you are seriously out of kilter.
FF, there is nothing to stop the RHS IR being utilisied to get the approach if to flown under IFR rules, PIC is merely transferred and an airbourne clearance requested by the qualified PIC.
On that point, is there anything that says that the PIC HAS to sit RHS or is it just the way its always been done?