After long consideration and deliberation over the NEC, the thought of home made power 'centers' located close to lots of water made me stop far short of building my own. Just too much added complexity waiting to break/leak/short/arc/explode IMO.
so... I hired an electrician who ran a new AFCI circuit to a GFCI protected 4 gang on the tank wall ( 8 outlets ). By my estimate, That will be enough for a basic 50g FOWLR without having to run extensions or powerstrips.
If it was feasable ( or economical - my walls are plywood ) I would hire an electrician build those controls into a wall away from the tank ... sounds great, but I'll just have to wait for an in-wall/basement sump project for that one.
HTH and
to all that do these on their own -
good luck and be safe.