So I was just wondering if it would be possible to get building MK4.
Inspired by Zisteau series I wanted as well to make whole base in one MK3 building but I got hit by a limited number of input/outputs.

If there was a MK4 with let's say 128 in/outs that would be great ;)

You could use a mod such as the deep mine or npbees so that the ores are made inside the base instead of brought in with a limited number of connections.

You could also use Deadlock's Stacking Beltboxes & Compact Loaders so you need x times less belt of input, that you can then decompress as needed. The mod allows you to change that factor.

It also adds an extra layer of depht in planning around since you need to take the unstacking into account. And if you're a masochist for planning, you might want to take a look at Deadlock's Crating Machine instead.

I'm personally using a factor of 4 so one stacked lane equals four unstacked ones.