The Nintendo DS came out in 2004; the GBA, in 2001; the GBC, in 98. See a pattern? The next Nintendo portable should be around any time. My guess is, it probably was already designed by late last year, and they aborted the whole process, to incorporate what they learned from the Wii, and hopefully the iPhone.

Here is what I predict it will look like, in no particular order — I'm privately calling it the “Nintendo DT”.

• Two screens, like the DS, but both multi-touch, either 512x320 (more likely — that's “computer widescreen”, 16x10) or 512x288 (“true” widescreen, 16x9, might be chosen in order to make the device just that little bit narrower).
• No physical buttons, except for power, and possibly L/R. All controls are via touchscreen (and accelerometers). Or maybe it's too early for that, since haptic tactition emulation isn't usable yet; in that case it may keep controls similar to the DS Lite, making the bottom screen smaller (4x3 — 384x288). Possibly an analog nub. Two, if they really really feel like one-upping Sony.
• Video codecs and player built-in so you can watch your movies on the go (a must with the widescreen).
• Camera either built-in or sold as an add-on.
• Probably no stylus at all.
• Definitely no GBA compatibility. (But the homebrew scene will have an emulator — VBA probably — up in weeks.)
• Better Wi-Fi; at least 802.11n. And Bluetooth.
• Browser built-in.
• More built-in storage, maybe an SSD or even HD (hope not); WiiWare is making a lot of money, and for watching movies you'll need space too. Maybe an SD or MicroSD slot?
• Maybe music player software built-in as well. (Can anyone say MarioPod? Or is it PokéPod?)
• I wouldn't be too surprised if it uses Cortex CPUs.
• “Slave mode” where it basically becomes a souped-up controller (with extra display area) for the Wii. Hacked in two or three months to become a “slave” to a Linux machine; practical application for the hack doesn't arrive for a long time, if ever.

Oh, and I'll probably buy one, install some Free Software, and use it as my “netbook”. Sounds great for media and writing on the go ;-) Unless, of course, the Pandora arrives first...