You might need a scanner every so often, but they're far too big for their occasional usefulness. If you've got an iPhone and some time to cut cardboard, you can ditch some paper and capture documents without the glass bed.
University of Cincinnati student Kyle A Koch frequently synced his iPhone and backed up his iPhoto library, but wasn't so hot with the paper and study material organisation. Since he knew he was reliable with iPhone images, he put his industrial design studies into practice and crafted cardboard-based docks that elevate the phone just enough to properly frame and capture 8.5x11 documents.
You can order a customised, pre-assembled version of Koch's scanner apparati in cardboard or medium density fibreboard, but Koch also includes a free EPS file for downloading and DIY building. It builds roughly 15 inches tall and long, and would seem to be pretty cheap to build. Combined with a universal capture/OCR tool like Evernote and the powerful camera on an iPhone 3G S, it's definitely a workable scanner solution for those who only need a few documents in digital form now and again.