Not really possible. The first and biggest problem is graphics. I am never a 3D graphics artist. I can only reuse vanilla graphics or if some users can contribute nice fitting graphics, which is a really big limiting factor to any unusual ideas. 2D graphics (like item icons, GUI icons) is my maximum capability.
Secondly, the game mechanics is written in a way that, if pipes of different capacity/pressure (tiers in my case) will perform EXTREMELY poor when mixed together. They must always be intermediated by entities that push up fluid pressure (pumps in this case) to its capacity at junction output.
So such kind of "unpowered" connector pipe of different sizes on multiple ends will not work at all.
If you want a "powered" connector (that works for different sizes), then my current pumps can already do the job. The high tier pumps are wide enough to be used like that.
And saving space is never a concern of this mod. Every entity is supposed to be scaled up in the same factor.
Not to say, a nuclear plant of high tier have already saved much space, compared to if one have to do that purely vanilla.
Say, a +4 plant is 16 times in size offering 256 times in power generation. For purely vanilla, one need 256 times in size to offer 256 times in power generation. You are effectively using only 1/16 space of vanilla. You are already saving lots of space by using this mod. ;-)
