Finally found a bit of time to work on a #Pinboard to #Raindrop converter/importer that will retain public/private and to-read/read status. First full test looks good, comparing the main Pinboard stats as seen in Tinboard with what ends up in the Raindrop website.
I think this might be doable and usable.
Once I've tidied up the code I'll publish it on GitHub, make it available via Homebrew, etc.