Well, you can buy a pbook version of The Necromancer from Valancourt Books -- they're republishing the "Northanger Novels." But I'd love to have them in ebook versions, of course! I keep meaning to write to them and ask them to publish Mobi versions...they'd be DRMed, of course, but I like the introductions and notes they've been including in the series. I remember looking for ebook versions of the horrid novels years ago when I first discovered Project Gutenberg...
I wonder if Chawton Library has them? Hmm.