Was reading this old thread: Can I send forms directly to another server (S3) and avoid upload to Wordpress?
And just wondered if Gravity had developed anything new, and also to point out the Chris’s solution is nor correct or at least omits some very important information. The dropbox connector DOES NOT bypass wordpress or your server. It uploads to your hosting first (briefly) and then is uploaded to dropbox (then the file is deleted from my server). The problem being that the upload is still subject to the file size limits of my server.