I've thought about the solar showers but we tend to camp in the mountains and camp year 'round so there are times when it's cold and there isn't much sun.
Propane is abundant and something I'd have anyhow for the camp stove.
Hiking is another story. She sucks it up for that but has yet to make a long trip with me and if given the choice between 2 campgrounds will always go for the one with the shower. I've considered the small solar showers for hiking just for myself...roughing it is roughing it but a shower sure does make you feel better after 8 hours of hiking.
The propane heater (zodi or otherwise) has many uses. But the last thing I want is another piece of junk taking up space. I wish I could find pictures of the inside. I bet one could build one like the Zodi stovetop model fairly easily.