How can you price something that doesn't exist? You don't even know what features or hardware it has.
Although using the 3DS you can somewhat predict the premium price of the new generation.

Also if you look back at how the 3DS was being priced between consumers, for the final retail price you take the mode wished value and add 50 to it. So for this imaginary Wii 2, it is 350.

Considering that the 3DS is going for £229 ($365), I expect the Wii's successor to be £250 ($398)

This depends on the US economy and the strength of the US dollar. As pointed out the US currency and economy's collapse is over due. Sooner or later the US dollar will spiral out of control downwards, probubly putting it around the value of the Peso or Yuan meaning it could be as high as 600USD.

However I will guess based on the Canadian dollar as it will likely rebound. I'd bet around 300CDN. Or 299CDN as it will look like on the label.

600$ and they will tell you to get second job if you can't afford it ;)

Overwhelming success seems to make bad things with top executive common sense.

But that would mean Nintendo copied Sony and they do not do that. They will tell you to get 3 jobs and sell it for 700 instead ;)

Anything between $329-$399 is my bet. Anyone who thinks console will be cheaper than that at the beginning of the next gen will have the most unpleasant surprise I fear.

Either $250 or $300 sounds about right.

I say US299, but only if they don't add some crazy and pricey gimmick, like built-in coffee machine.

same price the wii started off? i doubt Nintendo will make their consoles overpriced, Nintendo never does.. They would "as usual" make there system affordable 

Not knowing what they will do to differentiate the Wii HD model from the already existing 360/Kinect and PS3/Move systems it would be next to impossible to guess. If we just assumed it will be a better performing higher spec version of the older system then yeah same price or little higher but as this would seem to be unlikely it would seem logical to expect a higher price tag so $350 - $400 but as we know nothing about any Wii HD system it would be pure speculation in the extreme.