feature: minimalist non-interactive X backend for remote use

Hi mpl developers,

Over the last months I've become a great matplotlib fan. There's one thing that I miss a lot:
- a non-interactive X backend
that is fast to use remotely.

The GTK and TK backends have too much overhead for remote use, they're pretty unresponsive. The non-interactive backends all output to files.

For analyzing data that is on a remote machine, one now has to either:
1. transfer data to local machine to analyze (quite an effort if it's much data)
2. analyze remotely, generate remote graphics file, transfer graphics file, open graphics file locally to inspect the result

Both options are far from ideal, and having remote data is not an uncommon thing.

In IDL (interactive data languge), there is such a low-level, non-interactive, X 'device' that one can plot to. It is as fast for remote uses as for local uses.

Unfortunately, I'm not an X expert myself, but I'd be very interested in collaborating on a 'minimalist X backend' effort.

Is anybody interested?