For example, I think it would be cool if the ceiling was made of large rectangular solid wooden panels that could actually be lowered by cable winches. You could store big things on top of them when they are lowered (like power tools, maybe even a spare bed), and then winch them into the ceiling when you aren't using them. That would solve the problem of tiny houses generally not having enough room for large space-consuming hobby things like power tools, web servers and bulk supplies (@AgileTurtle).
Those kinds of things interest me greatly. The trouble is that it's largely more efficient to store stuff in, say, an open attic on shelving, unless you're making your ceiling extra-deep and have a bunch of airspace instead of insulation up there. But things like a storage-couch, pop-up tables, (interior) shelf-walls, and multi-use furniture that aren't typical construction are worth considering.
I'm also interested in the idea of combining a Soylent diet with a tiny house, since one of the largest things in most tiny houses is the kitchen. Eating Soylent would free up that area for more living space.
I'm dubious about this. I don't know much about soylent-diets, but having
no kitchen sounds sketch. You could easily have a 1-basin medium-large sink for multiple purposes (dish washing, food prep, hand washing out of the restroom, etc.), no dishwasher, a small refrigerator/freezer, and a small (possibly semi-portable) cooktop/oven and have a fully functional kitchen inside of an otherwise tiny house without wasting space - something like 16 sq.ft. could fit that kitchen with full-sized appliances. Your work surface could also be your multi-use table/floor/desk. Then you're not trapped into a tiny space with no cooking ability if you learn that you can't survive on soylent.
For guests you put on a covered patio addition and use used sliding glass doors as the walls. You can build these for $15 sq foot. Make it as big as you like. Put a nice propane fireplace in if you like.
Patios are a
great idea for adding cheap living space! If you just enclose all your 'critical' stuff (bath, kitchen, bedroom), you could live the large-house life and barely notice in the right climate or with the right living-environment plan.
My thinking with a tiny home is also to focus on design such that it is naturally solar heated most of the time and also requires no AC. If you make it a very tight space with very high R values. If you do this, you can use a solar/battery system for all your power and supplement with a fancy ceramic fireplace heater.
With houses this small, you heat them with body heat. A grown man counts for 300 BTU/hr, women/children are 200-250. No need for heaters of any kind, though having one is a probably good idea in colder climates.