I'm not sure if they still have older Macs, but I remember a shop in Columbus called Macmobile. I had walked by the store in 2001 and there were a ton of old Macs in the window, including a Classic II. (My cousin actually bought me that Classic II for my birthday that year; may as well talk about a conquest of old in this forum). I later called them and ordered an SE SuperDrive over the phone (I had a friend pick it up for me). The prices were good and the people I had talked to were top-notch.
I also saw vintage Apple equipment on sale at a church rummage sale in German Village (in Columbus) once. However, this was many years ago and the stuff you'd find in surplus these days would probably be iMac G3s and possibly 5200s, not the older Macs I'm assuming you're after.