I needed a soft case for my Samsung NC10. After some searching I settled on the Caselogic PLS-9 Ultra Portable 7-10″ Laptop Sleeve.
Buying this sort of stuff is always pretty hit and miss but in this instance the sleeve fits perfectly. The pocket on the front is big enough to store a mouse and has a pocket for a thumb drive if you carry one around to transfer files or backup data. You could probably fit the main power cord/converter in there instead of the mouse if you squeezed it.