I've found this futuristic device on James
Kendrick's Blog but reading his article I've discovered that DualCor cPC is a reality! 
DualCor cPC is a device that is able to run Windows XP for normal
computing tasks and switching to Windows Mobile 5.0 when the user needs
more PDA type functions.
It has a dual processor design, a Via 1.5 GHz
processor running Windows XP 2005 Tablet Edition for standard computing
functions and an Intel chipset running Windows Mobile 5.0 Phone Edition
for handling PDA and phone tasks, with an 800x480 Touch Screen and all ports
that a standard PC has (3 USB 2.0 ports (2 Type A, 1 Type B), a mini-VGA port,
stereo headset port, telephone headset port, and a CF Type II slot)
I think that this device moves the mobility world to a new era, where
we could bring together on a single device the power of a standard notebook
(or Tablet PC) and the features of a standard Windows Mobile Smartphone for
business. You could have a single device to make phone calls, check your
contacts, fix appointments on your calendar, work with Office applications,
manage your files, your images, write code and test your applications... all
this when you're on travel, sitting on a train or in a conference room.
Wonderful!
I hope to have more details on this device soon... the new Mobility
generation is here... 
Update: I've missed to say that this device has 1 GB of memory allocated to the Windows XP side, while the Windows Mobile side has 128 MB of DRAM and 1GB of flash memory. Both sides of the device share a 40 GB hard drive for permanent storage. Now the answer fot the first question that everyone of us want to know: the price? The device is expected to be available in March for about $1,500!