I need an application/interface/etc to retrieve from dropbox (i.e. we want to upload from Dropbox to a remote SFTP server). Essentially, we want to have a third party retrieve data/files on dropbox via SFTP. Is this possible? If so, how?
Dropbox doesn't offer an SFTP interface, but I'll pass this along as a feature request. I can't promise if or when that might be implemented though.
Dropbox does offer an API that works over HTTPS though that you can use to programmatically upload and download files, among other operations. You can find everything you need to get started with the Dropbox API, including documentation, tutorials, and SDKs here:
Note sure if you are looking at CSV files but if you are you can do this with EasyCSV.io. You create an import page & scheduled fetcher to get the file from Dropbox and have an import page you set up push the file up to the SFTP server you specify. Full disclosure I work for EasyCSV.