I have toyed with this idea for a while for all of the same reasons and equipment
you have mentioned, including the dive compressor. I am also looking to add engine drive refrigeration
to the mix.
I am considering auxiliary diesel
engine to use as a DC generator
, power a water maker and power a hydraulic pump for all the other systems. Emergency
high volume bilge/trash pump is a idea I didn't think of. I like it.
Please let us know how this works out for you.