Pretty much agree that it will be joint if not the big countries- I thought that maybe a joint British bid would work but then I remembered how positive the GB Olympic team proposal was thought of at first.
I'm not even sure how the joint Scot/Irish/Welsh bid would work anyway.
By 2016 the tournament will be a 24 team tournament. The current 16 team tournament has 8 stadia, all of which must be >30,000 capacity. As such one would expect at least 10 stadia to be required.
The following are the stadia that host Football in each of those countries that meet the capacity limitation:
Ireland
Lansdowne Rd - 51,000
Next Best RDS Arena - 16,500
Wales
Millenium - 74,500
Next best Cardiff 26,000, Swansea 20,000
Scotland
Celtic Park 60,000
Ibrox - 52,000
Hampden - 52,000
Next Best - Pittodrie -22,000, Easter rd 20,000
So thats 5 stadia that meet the criteria. 3 of which are in Glasgow.
At a push they could use Croke Park, although that is also in Dublin, and Murrayfield instead of one of the Glasgow Stadia. That would leave them with having to upgrade Cardiff, Swansea, Pittodrie and Easter Rd, and would leave us with only 6 host cities, ina tournament with 3 countries hosting it (Glasgow (2), Edinbugh (2), Aberdeen, Dublin (2), Swansea, Cardiff (2)) - 10 stadia, but only in 6 cities. It would be somewhat of a logistical nightmare...