Roomba not small enough for you? Well, iRobot's upcoming Scooba 230 looks like the tiniest little robotic floor cleaner around.
At a mere 3.5-inches high and 6.5-inches in diameter, it shouldn't have much trouble fitting under and around your furniture. And unlike the Roomba, this one's a mopper: it washes and then squeegees your floors, which is perfect for people with a bunch of hardwood and tile flooring. Look for it this spring.