Unfortunately I've neither the expertise nor the time to help out, Martin. My knowledge of QTI is pretty sketchy and I've not even downloaded Moodle, let alone familiarised myself with it. However, I'll put time aside to keep an eye on developments here. Our university has paid big money to WebCT and Blackboard so they're a bit committed at the moment, but I know that a fair few users are dissatisfied with those systems, seeing them as pretty clunky, so an Open Source interoperable alternative in the longer term may well be of increasing interest to our institution. Interestingly, I've just heard that Glasgow Uni is adopting it as the institutional VLE, so the more UK universities adopt it the stronger the case will be for Nottingham to go along the Moodle road.
Cheers
Fred