I also use hotspots while traveling or caching so please let me know when the list is up or if you need some of them checked, I would be more than happy to check some out.
Also I know of a few other ones that I can confirm.
Eggspectation in South Portland - Is advertised and have used.
Pannerra Bread in South Portland - Is advertised, will need to check
There is one in the Maine Mall food court but I am not sure where.
I will check to see if I can find anymore that Road Runner may have or any others that I can think of. Let me know if you want me to check any