cost of panel upgrade on bonanza

I am getting ready to buy my first plane. I am considering an early 60s
bonanza or debonair. Some of these planes don't have a standard "six pack"
panel layout, and I was wondering if anyone had an idea of how much this
would cost to upgrade. I probably would update the radios at the same time,
but I am really interested in the cost of the panel only.

Also does anyone know if there are any STC'ed conversions to a standard
power/prop/mixture quadrant for these older planes.

Thanks in advance for any help.