The Aberdeen Cup is not always going to be against England. They have thought ahead. In 2007 they are attempting to woo Spain to come to Aberdeen.
Murray v Nadal twice in a weekend
I think that the organisers would be best just to try and arrange two Murray v Nadal best of 3 set exhibition matches, 1 on Saturday and 1 on Sunday rather than a Scotland v Spain team match. Unless they can persuade the Spanish to not field most of their top 10 players, it's going to be a bit embarrasing - Jamie Murray v Juan Carlos Ferrero for example