If I recall -- I was reading the board + CPU was around $450, and you can pick up a x200 for ~$100 and do the mod your self.
The price goes up on the x200/x220s the nicer they look, and if they work, but you are looking at a max price of $250 if you don't wait for the good deals.
Ah, that's actually pretty reasonable. I've been looking for an x220 as a cheap laptop to throw a BSD on and tinker, but was always a bit hesitant due to the old architecture. This would definitely solve that! (I also like that the person in your link is offering a nice display upgrade.)
The price goes up on the x200/x220s the nicer they look, and if they work, but you are looking at a max price of $250 if you don't wait for the good deals.