[GraemeJ]

Agreed, you do need a decent size tablet, but that's only to be expected when you consider the whole idea is to replace A4 sheets of paper.

Quite honestly, I think this is a truly daft idea and certainly not a cost effective one. Google Glass was some $1,500 - you can buy a huge tablet and get a substantial amount of change for that sort of dosh. That's not even considering its technical shortcomings. It will be many years before such a product will become available on the consumer market and at the sort of price the consumer wants to pay.