Are you stateside ATM?
store.apple.com/us/product/FB450 … TA4MzMyODg
1.8GHz Macbook Air for $1199
Should satisfy your requirement of size and weight as well as decent performance.
They do have a $849 Macbook too. It’s the recently upgraded one, not the old polycarbonate models that came in black or white:
store.apple.com/us/product/FC207 … TU5MzE0Mzc
Thanks, I am Stateside and I drop into the local Apple store now and then (lately, to play with the iPads)… 
Even an Airbook does not meet the needs “my friend” has for weight and size. Ultralight travel here means a month on the road on a single bag; the bag of choice is a Mountainsmith Daypack, about 800 cubic inches. It’s not even a full backpack; it’s a lumbar pack. Great for freedom on the road, not so great for packing a full-size notebook computer with power converter, in terms of weight or size.
“He” is leaning toward buying a cheap iPod and jailbreaking it for use with an external keyboard, or doing the iPad thing. The iPod is appealing for size and weight, of course.