Wood vanities and wood frames are not at all unusual in bathrooms. No special wood is generally used in my experience. In my current remodel, my vanities are quarter sawn white oak. My bathroom doesn't get that atmospherically wet so as to cause any problems - my bathroom door is generally open and a good fan would remove moisture - my understanding is many of them are set to automatically operate to run until a certain lower level of moisture is achieved.

Your inspiration photo shows some kind of wood immediately adjacent to the shower - that might be more of an issue since the wood would seem to be getting direct hits of water from the shower.

Not that you asked but I don't think I would want open shelves storing towels directly above a toilet :-).

I like both types of wood you suggest! Will do more research here before we choose the type.

With what product do you protect the wood? I read in previous posts about Danish Oil, does that work?

Our wood bathroom cabinets are finished with water based poly. Danish oil is a finish that similar to poly cures to a hard finish.

As far as types of wood, different types of wood will move different amounts, and this is not specific to bathrooms, but in general as the temperature and humidity vary with the weather. How much this is an issue will depend on overall home humidity control. Where I am winter humidity is lower even with a humidifier running than in my unaircondtioned home in midsummer and so things such as door gaps vary a bit according to season, even with quarter sawn oak.

Ply wood will move little since in different layers the grain runs different directions, and so cabinet grade plywood might be a good choice for the boxes/base. Quarter sawn oak, because of the way it is sawn is more expensive, but moves little. Faster growing, less dense woods such as the pine shown in your inspiration photos will move more, but will cost less. If your husband hasn’t built cabinets before, he should spend time reading fairly extensively since otherwise you may end up with cracked door panels and drawers or doors that stick as the wood expands and shrinks over the course of the year. It will also take a good amount of equipment such as large clamps for gluing up door panels beyond the basic table saw, paint brush and glue.

love the space. great job!

here are a varity of wood vanities that would look amazing in bathrooms. check them out im sure you will find something you like from these.

http://focalpointhardware.com/vanities-and-storage-c-11_1181_1184.html