Ambassador Manning?

With the resignation of Frank McKenna as Ambassador to the US, who will fill his post?
Hopefully another example of nepotism such as was Jean Cretien's nephew won't be repeated - but then I though Uncle Preston might be considered for the job.
Could Preston Manning be the next Ambassador?
Or maybe Peter MacKay? (probably too young)
Why not Mulroney - now that would be Bush's choice I bet.