Gene, I am going through the same sort of thing right now with my -6a. Not sure I have come up with my 'forever (or at least a year or two) configuration so I am just using the old panel as a support assembly and putting in three sub-panels. If, after a bit of flying, if I like what I have done, I will probably just ship the configuration off to Stein to use as a template for a more 'finished' solution using 1's and 0's to cut and etch aluminum. It has been a good adventure.
Yours is a much more polished interior than mine, but it still screams out to do a 'roll your own' for the black inserts to start. Lots of analog gauges to remove, who knows what you will eventually want to put in their place. My dos centavos.