Figure out how much buying new copies is versus, say, picking up used copies at a used book store (or, in my case, the library sales room where paperbacks are $0.35 each). If the money you save is equal to a new scanner (flat bed for ~$60? at Staples), consider buying a scanner and investing the time to dismantle the old books and scan them and pdf or ocr then make rtfs (to epub with Calibre) and you'll get what you want with out DRM
If you can afford a two-side sheet-feed scanner, even better. Just a thought. I have a sheet-feed scanner at work and I'm scanning a lot of old books that simply are not available as ebooks but that I don't want to lug around any more. It's worth me spending the time to put boxes of books on a digital card for my JBL.