This will probably not help you in any way, and I refrained from using it in my last post, but just to give you a glimpse of what's actually out there
AMD Mobile chips
The reason why I didn't include it in my first post was because it's a swedish site (not too many will understand or benefit from it in any way), but they are being sold, and quite cheap also (look at the 1.2 ghz XP($124.75)).
That's the lowest watt for highest performance, then (of course) there's also the xp+1800 (1.5) that draws 35 watts and cost the same as the 1.2 chip.
Hope that helps (?), and please forgive me, I tend to go on, and on, and on... about things.