I very much like the screen controller rumor and I think based on the 3DS pricing, success of PS360 (which started at high prices), and current success of pricey phones/tablets... a ceiling price is more realistically $400.
I'm betting with 75% confidence that it will launch at $350.
I was right at first mention that 3DS would be $250 and I think level headed thinking and taking into account these rumors and what I said above, $350 is reasonable.
I'd potentially pay it. Maybe wait for $300... just depends on games I guess.
As far as my ideas on specs and such...
I have two threads that go into detail on all this.
I see a full media enabled device, with bluray, android apps, wireless-n, 3-4core CPU, 1-2GB ram, high end video GPU, standard HDDs, USB (2-4), two packed in controllers (wiimoteplus and dualanalog w/ screen).
$350 with some basic games as Wii and 3DS both had pack-ins to demostrate new functionality.