I'd been thinking about a top of the range PDA (or ultra super portable lappy) - on the grounds that you can carry it more easily than a lappy, but, you'd be able to manipulate the files on it, use it to present slideshows etc., even if the screen is a bit small for longterm use.
I had a feel of one of the Samsung Q1 machines at Bett (Educational Technology Show in London) earlier this year. While it wouldn't be practical as an only machine, I think that it & one other laptop (+ external screen/ keyboard), might give you a good working solution. Not that I've got one mind, so not sure how good they'd be long term.
I also don't think that I'd ever get to be totally paperless. I like being able to write things, to choose the colours that I use, etc. I *need* paper, though electrons are jolly useful a lot of the time!