nintendo are smart, they will have a Wii2 (WiiHD or whatever) & a DS2 on the ready, but will continue to 'fine tune' it (delay release) until sales have dropped for there old systems. They still have alot to milk with the DSi & DSi XL - DSi Ware & DSi Virtual Console (which i'm sure the ability to play old Gameboy games would get a fair amount of sales) & a quality 1st party DSi Enhanced games would boost DSi Sales as well.
They have just released a Black Wii & DSi/XL, reminds me of the coloured gameboys they released before they introduced the coloured screen... I suspect they will release a WiiHD, and montion plus controls built in to the remote, but will prob see how the PS3 motion controlls goes for the first 6-12 months to see if theres any changes they should make to outdo them.... but apart from that I doubt they'll invest too much into developing a new system
I cant see a DS2 being released so soon after the DSi XL - they are good at milking the market for all its worth & will release the upgrade when its a good business decision, not just because its ready now. Both the Wii & DSi are showing signs that a new one will arrive soon due to the variants released (black wii & Dsi's) sales is the only thing that will determine which will come first & when. & they will prob release them a year apart as to market them seperatly would be better for sales.
I would expect a new wii christmas 2011 & a new dsi 2012 or the other way around if DSi sales are shit