Why does there not exist a combo system for wireless mic and wireless iem?

[khachai44]

This idea can't possibly be original with me...which tells me that there must be something beyond my paygrade that keeps this from happening. Why does there not exist a combo system for wireless mic and wireless iem? I recognize that both the FOH (or rack) component and the belt pack would have to contain both transmitters and receivers but is that really a big thing? While I've never taken either apart, I would think there would be room within each for combining...wouldn't think it would need additional batteries (I'd think a 9V could run both since I've seen both run on 2 AAs and some tech should be able to be shared). Certainly within the rack/foh component, loa array space wouldn't be an issue since both parts fit in a beltpack independently. Seems that most of those components have reached a minimal limit on size due to power and audio connectors rather than internals (even body packs don't "feel" like they're exactly full of stuff). Any ideas or do you know of such a beast (of any quality)?