Maybe...though when I played with subclassing Net::FTP when trying to track down a mysterious bug some time ago, I found that once you start messing with doing the buffering yourself, you rapidly end up duplicating quite a lot of what Net::FTP normally does for you. I was more interested in finding the bug than solving the issues with the subclassing, so it's quite possible I was just doing it wrong.

I thought the tie solution was rather nice because it relied on a documented interface but otherwise left the internals untouched. Theory says that substituting a subclass of a module for the module itself should be simple, but the practice often proves otherwise I found. But, TIMTOWTDI. If you can avoid doing the buffering yourself, then overriding the retr method should work just as well :)