We just had one made for us for a narrow guest bathroom. It is very similar to this one from Sonia (our cab guy "copied" it for us in Walnut). Ours is the ~32" wide version (which Sonia makes), but I think our guy made it a little taller than the Sonia (gives us taller/deeper drawers). I'm pretty sure most or all of the Sonia vanities are pretty narrow (Ronbow? makes similar ones)

We will also have a recessed medicine cabinet in that bathroom.

It's not going to be a much-used bathroom, so we should have adequate storage (we'll use the drawers to store towels for that bathroom). In fact, we're considering having our guy make another in that design for one of the upstairs baths if it seems to work out.

We did get the white sink top from Sonia, as we needed a shallow depth sink in order to maximize the storage in the upper part of the vanity (and we really liked it, too!).

Here is a link that might be useful: Sonia vanity

We have a 19" deep vanity in our kids/guests bath, and it's fine. Since it's also only 30" wide, there isn't much room to sit things on top, but I don't like a lot of stuff on the vanity top anyway. You will probably want to use a recessed med cab, or just a mirror if recessed isn't possible. A surface mounted med cab would seem crowded, imo.

Just fine: most people won't notice unless you tell them.