What can I say, it’s a mouse kinda day. If the micro-sized mouse from Sigma isn’t your thing, the new Bluetooth MoGo mouse from Newton Peripherals just might be more your style. Gearlog has a brief "hand on" review (how do you use a mouse with two "hands") and while the mouse sounds interesting, it won’t be that helpful for UMPC devices. The MoGo is stored and charged through a PC card slot; something no Origami UMPC has. Still, for an older notebook (or the new Fujitsu P1610!), the MoGo mouse shows promise.
You won’t get a scroll wheel on this ultra-thin accessory, but that might be a small sacrifice for a wireless controller that charges in 30 minutes and is stored within your computing device.