$1000 for a laptop is not cheap. $400 for a laptop is cheap. At that price, you could literally buy a macbook and just install ubuntu on it if you wish.

I personally have a macbook pro, too, but just couldn't be bothered to add ubuntu to it, so I bought an old compaq off of craigslist for $350. Duo Core, 2gb ram, and 80 harddrive.

Now I have a laptop just for os x programming and cross-platform programming, and linux/(in the future)xp testing, minor programming as well.