Hmm, what I see is that the DS still seems hugely popular, is getting a massive push in stores, lots of new colors (this is in Japan), and of course the LL, tons of games, and just generally seems very "active."
It doesn't feel like a system which is being readied for phase-out, and I imagine they want to get at least one more holiday season out of it (at this point I'm assuming it's practically pure profit), and game devs probably feel the same way.
That's why I'd put any 3DS release in mid-2011, if not later, at least in Japan.