Hideo Kojima said that we'd still have a couple week's worth of speculation on what "A Next Metal Gear Is...", but rumored scans from Famitsu may have spoiled it. It's Metal Gear. For the iPhone.
Or at least that's what this scan, supposedly from the newest issue of Famitsu Weekly, indicates, a gesture based Metal Gear designed with the iPhone and iPod Touch's touchscreen controls in mind. From what we can gather from this heavily artifacted scan, it looks like it might be a spin-off of Metal Gear Solid 4, which may make it more action-oriented that the turn-based portable outing Metal Gear Ac!d.
Consider this a rumor for now, especially until we see something that looks more legit — and hopefully in higher resolution. If Metal Gear Solid Touch is what's planned and this is an authentic Famitsu scan, it wouldn't come as a surprise to many of us.
Famitsu 20081219 [Wii @ Everday]
UPDATE - Konami have since confirmed. The title will be called Metal Gear Solid Touch.