One of my weekend discoveries is this neat little two-in-one bathroom unit by Roca. It combines a sink and toilet into one, very space-efficient and stylish unit. I could easily see something like this being fitted into the smallest of tiny homes. Plus I love that with the lid closed, the toilet also serves as a place to sit (which any long-legged woman whose ever tried to apply lotion after shaving or pull on a pair of nylons in the bathroom should appreciate)
Although I have a feeling their fixtures are probably more expensive than other options out there and it looks like they distribute primarily in Europe, which could be a challenge to people in the States, the Roca website also has several other small sink and toilet options that are definitely worth a look.