Here in Australia we have one regional per state currently. To put that into perspective for those in the USA, that's 7 regionals spread across a country marginally smaller than the US.
And the closest regional to me is over 1300km (800 miles) away (and there are X-wing groups 300km (200 miles) further north).
I'd certainly hope that a regional was big enough to give me two games of gaming if I'm having to fly half the length of the country to get to it!
PS: of those seven regionals, only one is a single day event... But many gamers here come from the 40K/WHFB/FOW/WMH tradition, where two day events are pretty much the norm...
And from the old Dwellers Below podcasts it sounded like they were a blast.