When the 10M band is open, you'll hear many beacons in the 28200 - 28300 segment. As the operators are hams, I'm sure many would be open to sending QSL's. I recently e-mailed a brief reception report to N0AR for his beacon on 28255 and received an e-mail response, complete with a picture and description of the set-up. Other e-mail reports, to other operators, have gone unanswered. I don't collect QSL's, and my only motivation for sending reports is to let the operators know their beacons are being heard, though I do like to at least get an acknowledgement, or some kind of response. If you want a physical QSL, I'd think that mailing them a reception report with a self-addressed and stamped envelope would maximize your chances of receiving a physical QSL. If you have access to the QRZ database, many beacon operators give info about their beacons on their QRZ page, and QSL information may be part of that. You could also try a google search, as some hams have sites describing their beacons.
Not all hams send QSL's though. It's up to the individual operator.