Walt Mossberg's got an early preview of Lenovo's latest , the X300! It's also slim, not super-slim; but fits in a manila envelope. The X300 has a higher price point and starts at a full 1000$ over the MBA. No options on Hard drive configuration here- only a 64gb SSD ; comes with 3USB ports, WiFi, built in optical drive and options for GPS all packed in a 3.12 pound package that runs on removable batteries. Apple could take a few cues from this development and so can Lenovo (on the design aspects).

Update: More details have emerged about the X300 , and it has been spotted in the wild!

Update Again: Watch the X-300 taken apart. You'll notice the level of user serviceable components. Thats a big plus!