I would certainly steer clear of the medison, all reports I have seen scream scam.

As for the XO, you will be able to buy them in the USA and perhaps else where, but there is a catch. Its only available as a "Buy one, donate one" scheme, however it costs $400 (Thats 200 each), however they did say the $100 price was once they had it in real volume production and right now they haven't.

Thats the main point of this scheme to (1) Get firm orders for more laptops to they can get the price down, (2) Reduce the price for developing countries as they will have a stock of pre-paid for laptops to include with any order which will lower the unit cost.

If your interested (May be USA only) have a look at xogiving .org

Jen