This blows up if your hostname has no colon in it:

$ ./m2g-poller.py --host localhost -v3
Traceback (most recent call last):
  File "./m2g-poller.py", line 313, in <module>
    main()
  File "./m2g-poller.py", line 309, in main
    munin = Munin(hostname=args.host, args=args)
  File "./m2g-poller.py", line 29, in __init__
    self.hostname, self.remotenode = hostname.split(":",1)
ValueError: need more than 1 value to unpack

Also, can you create a gist with output of how this remotenode support works? I've never heard of such functionality.