I think when done properly - the decent hotel approach works much better than the casino on a UK basis, Raddison in Galway, EPT at Metropole - maybe I am just lazy and like to have my room, gym, spa, restaurant's under one roof when I go away - quicker to do something when I bust.
Based on that I go city wise....
Dublin
Barcelona (casino fab and ok as Arts near)
Nottingham for DTD
London
Prague
I guess the problem with a regional tour is the current volume in these cities - based on the success UKIPT and in a different way Mike Lacey and

events the key to me seems getting sats on the right sites with a deep reach inc France, Benelux, Scandies, with sensible buy ins and a decent structure.