That's a very nice looking finished product. It reminds me of Heathkit. You might make some money from your friends who want a case for their BITX 40 like that too.
I have tried boost and buck converters to use only one power supply and got a lot of switching noise too. Mine will have two DC input jacks also, but one will be 20V for the PA. And a switch to shunt over 12V to the PA from the main supply if I can't have both supplies plugged in.
