Sorry - to pop in here late to add to the WWR info re: Rio Futaleufu - but here's the deal down there.
The flights into Puerto Montt are no problem, but giong on to Chaitan would be. They only have a single airstrip there that can accommodate planes carrying up to 12 passengers give or take a few. They also have strict weight limits. The planes are always full with rafters, sport fishermen and avid climbers. The Chaitan airport is frequently socked in with fog and people may or may not get there on a specific day. In addition, the drive from Chaitan to the put-in takes about 3 hours.
Also, one rafting company owns the land around Rio Futaleufu and allows only a couple other outfitters to raft there. It's a class 5+ river and you have to pass a fairly rigorous test to be able to go down the river. All these things point to them not rafting there, as it would take well over a day just to get there, not to mention everything involved with actually being on the river.
However, the vid cap looked eerily like the "Fu", with its aqua color (coming from the copper in the mountains). There aren't many rivers that are that color - most are brownish.
That being said - I wish they were going there. It is absolutlely one of the most beautiful places I've ever seen and the rafting is the best ever. I'm looking forward to seeing where it actually is (so I can raft there too!)
Thanks for letting me give my $0.02.