I've been getting a fair bit of mileage out of the various notepads and tablets that I've collected at past OSCONS. Lots of pencil-and-paper design work, and these pads have been readily at hand.
But I do think it would be keen if the tablets were narrow-ruled instead of the usual wide-ruling. I write small, sometimes really small (depending on how intently I'm concentrating-- the more intent, the smaller the text). And lately, I've been writing two lines of text per rules line on the pad, because it's easier than having my notes appear to be double-spaced.
Just a thought.