Rumor has it that at WWDC, Apple will re-enter the sub-notebook business by releasing a new notebook that is apparently smaller than the 12" Powerbook. This notebook(I'll just call it the Macbook Nano), will feature a SSD, instead of a HDD to consume less power and space. Also, it may not even have an internal disc drive. Maybe that will just be an excuse you can use to buy an external Blu-Ray drive ;) . This Macbook Nano is aimed towards the Japanese market(they like everything small over there...), where Apple isn't doing too hot with sales.
HERE IS MY MOCK-UP OF THE MACBOOK NANO: