My first post here on eham... There are lots of 24V diesel Cruisers here in Canada. Most of us end up using a 24-12V converter with a power distribution block at the end.
I have the 20 amp Solar Converter in my BJ74:http://www.solarconverters.com/product_frame.html
I have a Rigrunner at the end of it, and just plug my FT8800 into it.
Guys with bigger power needs have used the Solar or other charge controller to charge a 3rd 12V battery, and connected all their 12V accessories to it.
A couple have rigged a second alternator to run a dedicated 12V system, but it's a lot of (custom) work and sucks some power.