I'm looking at existing python code that heavily uses Paramiko to do SSH and FTP. I need to allow the same code to work with some hosts that do not support a secure connection and over which I have no control. 
Is there a quick and easy way to do it via Paramiko, or do I need to step back, create some abstraction that supports both paramiko and Python's FTP libraries, and refactor the code to use this abstraction?
No, paramiko has no support for telnet or ftp -- you're indeed better off using a higher-level abstraction and implementing it twice, with paramiko and without it (with the ftplib and telnetlib modules of the Python standard library).
Does Paramiko support non-secure telnet and ftp instead of just SSH and SFTP?