You're getting a 30 inch WIDE floating vanity. The height of the medicine should not matter, the width of the medicine should not exceed 30".

As to sconces, it depends the position of the vanity on the chosen wall, and whether you have room alongside that medicine for whatever sconces you select.

Personally? I'd be looking for something in a medicine that is 24" wide by however tall you would like it.

Or, get more storage, and DON'T float the vanity at all. Have drawers etc. Then hang a free hanging mirror of your choice above.

But .....I'm not a fan of medicine cabinets on whole: ) They're never big enough, usually too squatty a proportion and the storage is shallow in depth..

We can't advise beyond that as you've no picture of anything you've selected, nor the bath you are redoing.

I have no idea why a 12' ceiling a bathroom and I love floating vanities but almost alwyas use Godmorgon from Ikea they have great drawer storage and i usually put a clet on the back wall for good support. I agree medicine cabinets are really poor storage for a bathroom. Good lightin is amust and sky lights are pretty useless on rainy days ot night time. So a lot more info please . The plan needs to get on paper not in your brain so we can see exactly what you are doing. Pics of the space and some real explanation as to the reason for the ceiling change. I am not great lover of sconces so more info gets more help.

Love our high ceilings!

There might be rules, but there are always exceptions to the rules! Go by what looks balance and works well for you. Doesn't really matter that some stranger hates high ceilings or medicine cabinets!

Here are the ones in my master bathroom. Robern 24" W x 48" H x 4" D. My bathroom is bigger, but I would have made the same choice with high ceilings in a smaller bathroom. I also have a 52" H mirror in my powder room to make use of the higher ceilings. Most people go too small with their mirrors.

Just pay attention to the hanging height of the recessed medicine cabinet as it will have to clear the faucet height as you swing open/closed ... but you don't want it too high, so that you can't reach the upper areas. Shelves are adjustable. I'm short and can't reach the top shelf.

In hindsight, since mine was new construction, I should have chosen the 6" deep model, but the 4" deep model still fits lots of stuff.

I have the model with power, so I even have my electric toothbrush charger plugged inside and just pop my brush inside to charge or store it. No toothbrush left on the counter. Of course, my DH still leave his out!

Thank you, Chispa! I am in a condo building, so there are a few restraints, in that the next door neighbor's wiring is in our shared wall, so I cannot get the BEAUTIFUL Robern 40" high Murray Hill Medicine cabinet that I want, but I can fit the similar GlassCrafters 36" high. I just worried that it would look too high over a 30" floating vanity, but glad I read yours; I am going for it. Yours are beautiful and I like the sconces. I don't have photos because the work hasn't gotten very far, but my indecision on the medicine cabinet is holding things up. BTW, my best medicine cabinet was a 48" wide x 40" high Robern = 2 24" wide ganged with a connector so there was only one seam. It reached across an entire wall in a very small bathroom. My fave.

We have no idea from your posting what the footprint of the room might be, or how large the wall is behind the vanity, or which way the ceiling slopes.

Violetta, what if you surfaced mounted the medicine cabinet so you could get a taller one? My parents have used surface mounted ones in their last few houses as they were added after the bathrooms were completed.

I had to put in a surface mount in my first bathroom redo, and it bugs me every time I use it - it is a nice Kohler 24 x 30, and I love the clarity of the mirror, but I love the finish look of a recessed. Good idea, though.