there's a big rub that it isn't apples to apples here. the game day is way more valuable to these guys than in the NBA or even NFL. to give up one home game when they only get 19 is massive for all of the clubs. you have to take into account that you can only watch a few games on tv over there. you can't watch your team if you don't go, most of the time.
i like the idea of the league cup/copa del rey/etc. fans don't really care about that. but then again, neither do the clubs. they'll tend to rest the better players until it TRULY matters. but the US fans won't know that. a team of half starters would be enough if you get 2 big teams.
the NFL isn't sending the patriots versus the eagles (equivalent). london has had a steady stream of usually garbage jag games. it'd need to be something like that - a desperate owner who can somehow get a bigger club on board. probably a team that needs the money, such as newcastle, who also has some name recognition. they give up a home game to play liverpool in boston. or maybe manu at met life.