Wow, this would be really cool Chip! The ONLY thing that in theory would be more impressive would be if you could engineer a way to keep the fish in such a way so that they're visible from the sides, heck maybe even more than one side...or even indoors! That would be REALLY cool...the ultimate indoor fish pond. You can even coin your own name for your invention...'Aqua' something maybe. It would require some sort of clear material I think, and it would have to be arranged in such a way as to make a sort enclosed waterproof container, or "tank" if you will....hmmm...food for thought.
But yeah, start simple and make a saltwater puddle.
There are a myriad of reasons why I wouldn't do this Chip, not that you can't do it, but I wouldn't because of expense, incoming freshwater due to precipitation, and the very fact that I'm going to move the fish anyway in the winter...also the "why" factor. I mean the only reason to do a pond would be because the fish in question are too large or too great in number to keep in a tank.
If you could keep some large morays, groupers and such, and keep them there year round, that would be one thing. Right now all you have going for this project is the novelty factor in my opinion.
Bottom line, I think the fantasy is better than the reality. I've seen it done right, a tidepool setup, but by a public aquarium that has more resources than you.
I'm all for ponds, but throw some large Central American cichlids in there, or a group of mbuna - they'll breed and you can leave them there year round in your climate. I used to know a breeder who would throw cichlids in ponds in the summer, and they would emerge looking incredible.
Or a Redtail catfish. 8)
I guess what I'm saying is, if I'm going to set up a pond, I'm going to keep something in there that warrants that amount of space, which means I'm probably keeping out there 365.
Aside from all of that, I see no reason why you can't do it.