The only Youtuber I know of is not further along than you. There have been posts by people in the late game, but no full base walkthroughs that I'm aware of. You can see snippets of my own base on the mod page here, but not all the detail. I completed the end game objectives with my base. It has areas for smelting the basic ores, feeding into a pretty standard (though wide) belt bus for intermediate products. It also has a fluid bus, using compressed gas when possible. Actually there's kind of a second belt bus for some of the more advanced materials, since it wasn't super well planned out, and that one is mostly stuff in boxes. Then all of the buses feed into a small mall area, which is the only part of my factory with bots. That creates all the structures and building materials that I use for my factory, with logistics chests. Most finished products only require a single assembler crafting them, with lots of modules. This is also where I create my physics science, since they require a lot of high end stuff (in small quantities, due to the number of physics packs created by the recipe), and launch rockets from.
My production is highly interconnected, so I do make full use of almost all byproducts whenever possible, but obviously some things do need to be vented since the ratios are never going to be perfect. And sometimes with very cheap byproducts I'll just vent them rather than pipe large quantities of something long distances.
After completing the end game goals, I did get started on a train-based megabase, but once I released the mod I got too busy with supporting it to actually spend enough time playing it to keep going on a megabase. I may get back to that later.
