In search of jack-enabled visualization app

[Ken Schutte <kschutte@xxxxxxxxxxxxx>]

Hi,

I'd like to find something that can take arbitrary jack inputs and do 
some real-time visualization.  Preferably, show some spectral analysis 
and can display full screen.  I'm thinking of trying to put something 
together myself, but it would be very helpful to at least find something 
to look at for a place to start.  Does something like this exist?

thanks,
Ken