Down the road a Pens-Flyers game at Beaver stadium would be awesome. 110,000 people at a hockey game would be insane. Detroit-Columbus at either Ohio Stadium or Michigan Stadium would be sweet too.
I read something about using the Rideau Canal in Ottawa as a venue, I guess erecting temporary bleachers.
I think football stadiums are a better choice than baseball stadiums, just because at Wrigley and Fenway there was all that space from the rink to the outfield bleachers.
And for jerseys for newer teams they would probably just create something retro-ish, like the Wild have done with their home and alternates.