I would like to set up the Raspberry Pi as a simple box that runs Concerto exclusively. That way I can use an older TV as a screen.
Are there any tips or better solutions out there that I don't know of? Thanks!
Yes you can!
Remember, the client is just a stripped down debian install running firefox to access the concerto bakend. So all you really need to do is run a fullscreen firefox instance! The best bet would be to set up a bash script that runs on boot to automatically start firefox in fullscreen mode and point it at your concerto server.
The custom concerto client iso that is supplied will not work because it is only designed for the x86 architecture. Also running RPI software on the Rpi? It's like a match made in heaven!