[Dan22]

Neither I am.
I think there would be many issues
1/ as Glasgow Celtic said, problems for the team travelling in London. Could you imagine how tired could be the teams coming from the Western Coast like the 49ers or the Seahawks?
2/ I don't see players playing for the London team being very motivated in playing for a team which is not in their country, being far from their family and supported by a very heterogeneous public coming from various part of Europe (and obviously a public who couldn't afford to go to London at every game)

That's my humble point of view