Thanks to all those who responded (I don’t propose to reply individually). The good news is that there is certainly enough interest to progress this further. I’ll keep you informed of developments, but whatever happens it’s unlikely to be until some time in 2012.
I had a really badly timed email glitch last week and may have lost some messages. I received a couple of private replies (as distinct from publicly visible comments) but if you used that method of response you might like to send it again just to be sure. (Apologies for this imposition.)