I like the fact that one of them copies the Rev. It would be smart marketing on Nintendo's part to reinforce the Rev in everything from now on, and constantly drive home that look. If the GBA2 + DS/DS2 looked like it, it would present them as a family of products, which would only help to increase Nintendo's image and broaden the gaming market/spectrum.
As for the redesigns, the linked one is okay except that it includes an analog stick, something that won't happen. Additionally, the "touch mode" incarnation wouldn't be feasible because there's yet to be a game that is wholly dependent on touch input. You'd still need access to some face buttons, especially start/stop.
I like the second one better, but I sincerely doubt we'll be getting cool transforming machines if only for the fact that an increase in movable parts = greater potential for malfunctions: power cords coming loose in the machine, plastic breaking down, hinges wearing out, etc. That would be a PR nightmare. Given that people of all ages play these things, and that kids are a huge demographic, I really doubt they'd allow something that could be fragile even in the slightest. Nintendo's machines are the msot durable around, and it's mostly because they aren't doing crazy stuff with them.
However, *if* Nintendo went that route, then I'd love to see that design above, but with the ability to - as Pale mentioned - only see one screen for GBA games. That would be awesome. Morph it into a little square for travel, and then open it up based on what game you want (DS vs GBA).
I think we'll see something like the SP - it will be more square shaped, hopefully look iPod/Applish (white, oooh baby), and have the controls under the screen as opposed to the side. Something that is minimal, but doesn't go overboard with movable parts. Of course this might affect how well someone can reach touch controls midgame. Hmmm. We'll see. Nintendo never fails at a redesign imo.