Yeah i guess request bingbonging would work in this situation, but honestly though, I still think it's kind of an awkward mechanic and i'm not so sure about requiring players to design around it by incorporating it into Official Botania Game Mechanic Canon to justify not adding more corporea stuff (You can request all * but can't easily request 1 *, for one, and it feels more like an arbitrary limitation than something interesting about corporea. In the limit, retainer ping pong means corporea funnels themselves are entirely redundant, just pingpong corporea index requests forever)
"red string for item frames" -> Just a red string-like block that binds to itemframe instead of a block entity and exposes a one-slot inventory, if you add an item to the inventory it gets displayed on the frame, if you remove an item it gets pulled from the frame. (I was also thinking about some kind of "ethereal frame" that makes a copy of items you display on it & doesn't relinquish them, might be handy)
Corporea spark augments -> are kinda eh honestly, i dont think the use case is very strong apart from "but regular sparks can have augments" & you now have to walk the whole network just in case there's 1 dominant spark you'd have to pull from first