I suspect that Argentina, Brazil, Holland and France would win theirs, but don't think that any of the following would: Germany, England, Italy, Spain.
Answering my own question here, but there's a strong relationship between the first group anmd how many national players play in their own leagues (i.e. hardly any) and the second group (the majority).
USA, Ecuador, Sweden, Norway, most African teams, Ireland, Wales, Czech Rep, Switzerland, Belgium (maybe), Aussies, most Carib nations, most central amer nations (cept for mex), a lot more probably.
Germany wouldn't win the German league. I doubt that England would win the Prem. And Scotland wouldn't win the Scottish Prem.
Assuming we cloned the players, Bayern would be a better team than the German NT. Particularly in defense.
Argentina, Brazil, Holland. Also all the Latin American countries, since most of their national players play in their leagues.
They could, yes, but I still think Bayern's a better team. ----------------Kahn--------------- ---Sagnol--Lucio--Ismael---Lahm--- --------------Demichelis---------- ---Deisler-----Ballack----Schweini/ZeRo-- ---------Pizza-------Makaay------ ---------------Kahn-------------- --Arne---Merte---Metze--Lahm-- -------------Frings------------- ---Deisler----Ballack----Schweini-- --------Klose-----Poldi--------- Comparing possible starting XI's, the glaring difference has to be the defense. Lucio/Ismael/Demichelis is a stronger defensive core than Merte/Metze/Frings. The German NT would kill for Demi right now. Arne's solid, but he's no Sagnol.
South Asian countries who are doing well economically nowadays, such as Malaysia, Singapore, India etc. could not win their national leagues. There are too many foriegn players in their clubs who are a lot better than the local players.
I think Mexico could win their league, and the US definitely would. If we are cloning players England might win the premiership, but if you took away all their players from their respective clubs and played them in the national team only I think it would win.
Without ever having seen either the Qatari national team or a domestic game I would venture to say that the national team would have a hard time winning the league.