> I guess it is part of the reason that I'm asking the question, as if we also know that the rft was a website, it would be very odd behaviour (I think) to use an http URI in the rft_id that wasn't the website URL?
True. How, from the OpenURL, are you going to know that the rft is meant
to represent a website?
But I still think what you want is simply a purl server. What makes you
think you want OpenURL in the first place? But I still don't really
understand what you're trying to do: "deliver consistency of approach
across all our references" -- so are you using OpenURL for it's more
"conventional" use too, but you want to tack on a purl-like
functionality to the same software that's doing something more like a
conventional link resolver? I don't completely understand your use case.
But you seem to understand what's up, so you can decide what will work best!