A VRC component that could be added to the root of the avatar, where you could have a list of blueprint IDs too.

This component would be accompanied by a global integer parameter that would not only save what variant you were in when you last switched out of the avatar but could also be set via a parameter driver to switch to another variant of the avatar.

When selecting the avatar in-game for the first time, you would swap into variant 0.

All avarat variants would need to share the same list of paramaters so if you where to reset your avatar it would also reset all the variants.

Pros:

You could have a more complex avatar split into smaller parts that each could be more optimized than the whole.

It would be an easy way for creators to sell more feature-rich and optimized avatars at the same time.

Cons:

Could potentially increase load on VRChat servers if people swap avatars more often.

Might be used as a quick fix to optimize avatars rather than trying to actually put the work in to optimize it.