For me (and my definition!) it depends on the screen resolution. All the other specifications look about right.
It’s the Seamless Internet S-Xgen and its got a 4″ screen which could work with an 800×480 resolution. If that’s the case then yes, it could be as useful as a UMPC. Otherwise you can forget rich browsing which is a big part of the appeal of a UMPC.
Apparently its got CF slots, USB, WiFi, Bluetooth and cellular radios too. My guess (based on the fact that the screen doesn’t appear to be heavier than the keyboard and that the keyboard is so slim) is that its a RISC-based device running either Linux or CE/WM5. The companies CES page also hints at a WM5/CE device.
Its certainly interesting and at $600 its way cheaper than the new HTC smartphones. Could it be an incarnation of the Carrypad concept device?
The S-Xgen reminds me of the Road S101 Handy PC that I forgot to write about a few weeks ago. Its a RISC/Linux combo device with all the radios you need and a rather useful/Psion 5 looking keyboard. This one only has a 640 wide screen though and it looks like it will be 1400 Euros when it launches.