Here's an option available now in Europe for cheaper than the expected price of the iPad here, which dual boots into either Ubuntu and Windows. It's a 10" slate with a 160 Gb HD from the Italian company Ekoore, and has the additional ports and webcam you want:
http://www.expertreviews.co.uk/lapto...pete-with-ipad
The video is impressive. Battery life will probably be lower than the iPad, but the machine is more open and more powerful.
Grahan