[RELATED_ARTICLE]A round mouse built with aluminium, the Asus WX-DL is wireless (2.4GHz), has a 1,200 dpi laser sensor, and currently costs $79 Stateside. The round body is slightly raised at the back, to better and ergonomically fit in your palm. The black circle on top is touch sensitive, which will supposedly allow for four way touch scrolling, and, also offer multimedia controls. Button-less just like the Magic Mouse, the WX-DL will still offer left and right clicks.
The device looks like it might be quite usable, and is compatible with Windows (from 2000 to 7).