Interesting but the need for using another system on top of retroarch is a No-No for me; if I'm gonna use a second front-end to launch an emulator through a front-end, I'm gonna use STEAM to do it as it comes packed with a social component that none of the other front-ends seems to have.
To me, Retroarch ends up as a pain in the tushus as it has a rigid file system scheme that interferes with how I organise my stuff. It's the same problem that MAME has, with how rigid it's filesystem is, which introduced a massive file redundancy problem as I wanted to keep things organised using my own system. I solved it by making Peace With God that every time I update MAME I'll have to download all the roms again etc but since I never had All The MAME stuff archived, that wasn't that big of a deal. The other gaming systems however are a different story.
Speaking of which: The image below is how I organise my filesystem, all in an external hard drive, for portability. Some assets are missing and there are no arrows indicating what-opens-what but I think it's easy to follow without any instructions.
A lot of those graphical assets are hand-made by myself so it's forever gonna be a Work In Progress; if anybody has a better idea on how I can organise this in a front-end agnostic manner, I'm all ears. The current plan is to eventually standardise all the file names and build a batch program that sets up all the icons and creates steam shortcuts using the files that are there; if you as much as change the name of any of those folders it's icon will revert to the standard folder icon so it's a pain in the ass to deal with when I have to format my computer, or if I plug my Throve disk into another computer.
I'd also like to point out that there are only two systems that use serial codes in the directory name; I deeply regret having done the PSX and Sega Saturn that way, as I can't find anything without using the search bar.