I have thought of a way to do this but I HAVE NOT tried it yet so I don't know if it will work.
1) Create a new user on your computer
2) Log in as new user and install dropbox
3) Set the drop box folder to be on an external drive (you can do this)
4) Under Selective Sync, un-tick every folder.
5) Start dropbox
6) Move your large files for upload to this folder
7) On all your other dropbox computers, under selective sync, untick this new folder so it doesnt download elsewhere
I'm pretty sure this will work, but it is a workaround. If dropbox wants to remain competitive in the retail market then it needs to address this issue. It should be much easier. I didn't pay for all that storage just for it to be unused.
Phil H. I have had my Dropbox folder on an external drive for two years. I used the move option to transfer it from the default location to the drive. I would think your instructions would work for this purpose.
Hello, you might be interested in Archiviste (http://hibou.qc.ca/archiviste). Use it to upload your files directly to your DropBox account. I suggest creating a "Backup" folder on your Dropbox account and uploading everything there. Finally, use selective sync to disable synchronizing this folder with your devices.