Ah too bad I don't have mod points. This is what I came to suggest here. It's truly the best of both worlds. I used to have one (received one as a gift), but as it turns out I had never up to that point taken notes in class, and having one such pen didn't change matters much. I did try it for its geek factor, and it was just fantastic. The software wasn't great (and it was windows-only), but maybe things have changed since then.
But if OP's wife is hellbent on getting a tablet (I'm starting to believe it's just one of those solutions in search of a poblem), what I had before the livescribe was an old-school tablet PC (with a wacom tablet and pen as the input mechanism) with Linux on it. There was a pretty straightforward program from the repos that was pretty great as well, it saved all the notes in an xml file, and was exportable to PDF. I bet it still exists... Yup, it's called Xournal, and it's in the Ubuntu 11.10 repos still.
I still don't get the tablet craze, I must say; that tablet was pretty damn cool (and an actual computer at that), and still I ended up selling it on account of me never really using it as much as I thought I would when I bought it.