"The mirror is here in the bedroom."
Translation:El espejo está aquí en el cuarto.
Would "esta" still be correct for, say, a wall-sized, permanently- attached mirror? Or would it then be "es?"
I would say yes, since you are describing a location. If you can think of a sentence that described such a mirror as a characteristic of the wall/room, then ser would work. Note that the temporary/permanence rule of thumb is generally hit-or-miss as a guide to using ser and estar.
J-bird4, location uses estar. The old permanent/temporary ”rule" is not helpful. Location uses estar, whether it is permanent or temporary.
Estoy en la biblioteca. I'm at the library. (temp.)
Madrid está en España. Madrid is in Spain. (perm.)
There is an exception to the location = estar rule: if you are talking about the location of an event, use ser: La fiesta es en la biblioteca. The party is at the library. La reunión es en la oficina de la secretaria. The meeting is in the secretary's office