Dang, you weren’t kidding with the price of a used x220 (I have an x230 that I got for less than I’m currently seeing on ebay a while back, and the only thing that really made me switch to something newer was the screen). Maybe a newer thinkpad or an hp elitebook? I think as long as you have something newer than a 2nd Gen I series chip, there really shouldn’t be an issue if you’re basically just using it for text processing. If you start with models with ddr3 and sata drives you should be able to get very cheap replacement parts for a while yet.

Smaller stuff has to be more complex to get to the lower mass, which is usually what causes the biggest issues. The hdds in those ipods had some extra stuff to make them more reliable, but even then, move them too quickly and they show it.