Is there any indication that this is the only way to increase carrying capacity? If not you don't need to dive into it. I see also that I'm going to have to find more perk space for a few speech perks.

My idea would be a suit of (as light as possible) items all enchanted with stamina boosts. In Oblivion I'd carry treasure to the dungeon entrance and dump it in a nearby chest, then I'd stack feather potions to carry it to town. Maybe you can make stamina potions and on top of that use stamina boosting alteration spells as well?
Granted that's only a temporary thing.