Assuming that I cannot run something like this with Fabric:
run("svn update --password 'password' .") 
how's the proper way to pass to Fabric the password for the remote interactive command line?
The problem is that the repo is checked out as svn+ssh and I don't have a http/https/svn option
You might need to supply the user as well?  If not, you may have better luck exporting your repo and making a tar of it (locally) to upload+deploy on the server. If you run the svn commands locally, you'll be able to get prompted for your username and/or password.
fabric and svn password