Yeah, this is the sort of thing that has driven me away from doing more than casual experimentation with Linux. And why I am glad that my needs for computing horsepower are modest, because it’s possible to get used Macs fairly cheap if you monitor your ebay searches and are patient.
Three possibilities that occur to me for determining if a particular model of used laptop is going to have all the needed Linux drivers, without spending extra money on a preinstalled one. First, there is a lively forum community devoted to Thinkpads, and they have a Linux subforum.
Second, http://www.thinkwiki.org has detailed info on every model of thinkpad ever, and there may be articles there about Linux support for the model you are interested in.
Third, If linux has some kind of centralized UI for seeing the machine’s hardware and seeing what components lack drivers (note my vast Linux experience here) you could make a live USB stick, use it to boot the machine you are thinking of buying in the store, and see what drivers are missing.
