Replacing bulbs in vaulted ceilings is always a problem but to the point here. I think all shower trims are designed to drain so you shouldn't have that goldfish bowl effect you see in jelly jars and other luminaires exposed to water.
At any rate once you get 8' above the rim you are out of the shower area as far as requiring "damp" rated covers.
410.10(D)... Luminaires located within the actual outside dimension of the bathtub or shower to a height of 2.5 m (8 ft) vertically from the top of the bathtub rim or shower threshold shall be marked for damp locations
