You can vent horizontally out the wall.

We obviously need to keep it economical, but I would like to do something creative, and I'm bored with our past designs (generally they consist of a larger field tile with horizontal accent stripe).

Yeah some horizontal wall running on the short side will always help.

Then create a patio/entry for each lower unit by a simple screen of an above-ground planter from the post to the stairs, or maybe at an angle to where the stairs begin.The rest is comparatively very simple... don't paint the brick, do the siding in a darker dusty green, the window muntins in a very dark gray (it'll match the black powder-coated hog wire balusters), get a very LARGE round fake attic vent for the gable,https://cdn.shopify.com/s/files/1/2196/8707/produc...and install a clete at the bottom of the gable which will look like a horizontal supporting member for the second-story columns.Lose those shutters, paint the entry doors a very deep, rich color, with the first and second story doors slightly different.

It goes up, peaks, goes down, bottoms and then goes back up again.HOWEVER, while it is a business cycle, most people only think of it as simply a cycle that moves against a horizontal line.

@Ben Kahle it’s not very innovative, but for assets that size we build a bank of parcel lockers using various sizes of something like this:https://www.mailboxes.com/mobile/products/4c-horizontal-mailbox-10-door-high-unit-37-1/2-inches-double-column-stand-alone-parcel-locker-4-pl5s-front-loading-usps-access/It’s much more affordable than the Amazon Hub and other similar high tech solutions.

Very large lot allows for many options on rebuild, to expand horizontally and vertically.

That's not simple, because there is no basement or crawl space; the tub is installed over a cable-tension slab.One possible solution I thought of would be to take out the tub, reverse it and install it a little higher, with a slightly sloped, essentially horizontal pipe running under the tub from the drain to the existing trap, a distance of maybe 45 to 48 inches.

Your situation is a classic example of vertical vs. horizontal income streams.

@Bill Brandt  with the cost of dirt the cost of horizontal and the cost of vertical  a 2k sq ft house  just those costs before profit at least in Portlandia is 300k minimum..