The Mogo Mouse X54 uses Bluetooth and should work on any surface thanks to its optical sensor, according to Newton Peripherals. It features a central scroll pad and is automatically activated when you flip it out your laptop's ExpressCard/54 slot.
The developers say it should be quite comfortable because of its deep finger grooves and the integrated "kickstand". I haven't tested this mouse yet and it's kinda hard to predict how ergonomic this mouse will feel but according to Newton Peripherals people who have used the MoGo Mouse X54 almost unanimously said that it's very comfortable working with the mouse.
The Mogo Mouse X54 will be available in the second quarter of this year. Unfortunately it's pretty expensive, the expected retail price is $79.99.
Hardware: ExpressCard/54 slot, USB Bluetooth adaptor or embedded Bluetooth OS: works on Windows XP and Mac OS X Bluetooth 2.0 EDR compliant Resolution: 800 DPI Working range: up to 30 feet (10m) RF transmit power operating: less than 4dBm Battery voltage: 4.2V Battery capacity: 90mAh Operating current: ~ 20 mA Internal Rechargeable Standby current: less than 10mA Dimensions: 3.1 x 2.125" x .2 inches (78 x 54 x 5 mm) Weight: .5 oz or 14 grams