I'd like to have "Dimension Energizer" or something, basically a block that could house multiple realized dimensions and keep them powered. Kinda like a Builder, but without the ability to build but the ability to house multiple dimensions. Making a builder for each dimension you want to keep powered, while not expensive in the late game, feels kinda stupid and takes up much room. (and in the not-that-late-game the huge buffers in each builders kinda kills power 😄 )

While I like compact designs, I'm still a huge fan of multiblock structures and especially if they are modular. So ideally the machine would be a multiblock structures, for example:

a) A Power Input block (you connect this to a source and it provides power to the multiblock)

b1) A Library Module (this could house 1 realised dimension)
b2) An Advanced Library (this could house 6 dimensions)
b3) "Ultimate" Library Module (this could house 1-x dimensions, similar to storage block lists stacks, in a scrollable list, perhaps a limit of 20? or 100?)

c) Interface Block (this is the block with the GUI and if needed any I/O functionality, like piping dimensions in/out of the structure)

The multiblock would function so that you could add an (in)definite amount of library modules to expand the structure as you need. (maybe a realistic limit like 16/32 blocks?). Crafting a higher-tier Library Module should be more expensive than just building multiple lower tier blocks, at least with the "Ultimate" block. Like you could require 8 tier-1 blocks to craft the tier-2 version.

Perhaps also have tiered power inputs, so that the first tier could be slightly less efficient than the next, and perhaps you could infuse the last tier to finally get to the point where the total energy needed would be slightly less than the dimensions would require individually (just slightly, like only require 90% power or so).

Obviously any numbers are just pulled out of thin air. And just as obviously I'd be deliriously happy with just a static block with an inventory space for 2+ dimensions, it's just that the multiblock would be cooler :D