It seems to me that the only credible alternative stadium is St James Park Newcastle
1. City Centre location, close to what is widely regarded as a great place for a night out - certainly compared to places like Manchester, Sheffield, Bristol etc that have been mentioned
2. Away from the heartlands of the game but not so far as Edinburgh or Cardiff, which would help with travel costs
3. A sports mad local populace who could be targetted with a huge advertising campaign, free tickets for schools etc. Might also help Gateshead.
4. A cracking stadium that would look full with 40,000 there, which I think is very achievable
Howay the lads