AU in the UK would be great, or Europe would be a good first step if numbers in the UK don't add up.
Current economic climate may present the biggest hurdle as getting sign off for ADA 2008 next week was hard enough!
Every other year may work well.
Mr. B started holding European conferences weeks after his USA event; lasted two years and no sign of a return in 2009. USA event is just to tempting which is probably the same problem with AU. We make the effort to cross the Atlantic because the events are so good and the welcome so warm.
Maybe a joint conference would be fun now Mr. A and Mr. B are cooperating with interoperability?