No plans yet, it's just something in the back of my mind -- is the process and cost prohibitive?
Depends
Keeping fish <--- isn't expensive or hard - pretty much the same as fresh except for the salinity and some different light bulbs if you want better looking rock ,etc...
When you start looking into corals - first you spend money, set everything up,curse alot,figure out something that works better,spend money. --- Any coral type questions ask Junior,I never really enjoyed non-fish things to put up with them long enough to comment much.
but the main costs:
filter
protein skimmer
and LIGHTING