You can put 1000:1 inside a building that's...I forget how small, but 25x25. That is HILARIOUSLY dense. Just increase the compression ratio, or, if you don't mind the 'cheaty' nature of it, set the compression ratio to the lowest value (25:1 for most things iirc) and then build them, save your game, exit your game (so go to main menu) change the settings up to 1000:1, and bam, you now have a building with 1000:1 outputs, but the same size as it always would have had. Basically, it saves you needing to build 1000x assembler 3s. Not sure if that gets you what you want, but, as far as land area goes, these are already hilariously dense, I'm not making them even more dense.