I can tell you straightaway that this is well nigh impossible because Ontario would have to agree with Quebec to change its dates, as then would Saskatchewan, etc. The legislatures could not respond in time; that couldn't be done. It would have to be planned well in advance and I don't see how that could be done because the decision to hold a constitutional referendum can be taken at the very end of the process as was the case last time. The decision was made in May or June.
On October 26th, 2010. See this statement in context.