Yes, well, seeing as it's all my idea, what I call the Ship Hull Integrator by Twelvefield (S.H.I. er...), I also would suggest that everybody here send me $5. If you do that, I will see to it that your "karma" gets a boost. And it's a grand idea, as all of my ideas are.
Seriously, though, I don't know whose idea it is. I'm just passing it on. I, too, love it in theory. I think as ideas go, it's probably even feasible. After all, the Ship Designer in GalCiv was added on as an afterthought, and it's proven to be one of the best things in gaming, period.
However, like you say, don't hold your breath waiting for it to come. The business model of the developers is the single most important factor in game design, and like most other game companies, the devs aren't making it public. We can make the suggestions in the forum, but I suspect the amount of weight of these suggestions is rather low.
Still, it's fun to speculate.
The Ship Hull Integrator by Twelvefield as I see it is just a way to make new ship designs by plugging in pre-made modular parts. The actual function of the ship would not be changed in any way. It's just a method to make flying saucers or star destroyers or space Elvises (but no space elves!) as you see fit.
However, people want to change out all the weapons, too. That would involve a Basic Armed Ships Twelvefieldian Advanced Radical Design tool, or B.A.S.T.A.R... well, I have to work on my acronyms. I would think that to balance out the ships as they stand, the devs have assigned some kind of internal value to each offensive and defensive system on all of the ships. Folks in the forum have certainly spent a lot of time and effort working out that system. To make the B.A.S.T.A.R. (you know) work, the user would have to be given an understanding of these values.
So, ship X can hold 1,000 points. Its engines must be at least 300 points, its armor must be at least 200, which leaves 500 points for gunses. As long as you can fit the parts into the ship, then it should work. I am over-simplifying, but you get the idea. There would have to be trade-offs: the more antimatter you need for weapons, the slower the ship goes, or the more missiles you pack, the weaker your armor, that sort of thing. As you advance up the tech tree, you'd have more advanced desigs waiting and ready to be used.
I would entirely expect that the B.A.S.T. etc. would create game imbalances, especially leading to multiplayer exploits. I would think that would be part of the fun. Eventually, the best libraries of ships would get published, and the really serious players would establish limits on which libraries could be used in their games, if any.
I don't think that B.A.S. (and so on) would be very different from the system the devs used to create the original fleets, only it would be accessible to the unwashed masses (us).
So, as far as speculation goes, this is a lot of fun. As far as expecting this kind of thing to turn up as a real add-on to the game, I expect none of it to happen, but it would be nice or at least mildly intersting if it did.