Sunshower is an interesting Amsterdam company with a range of shower lights with ultraviolet and infrared output.
I have long dreamt of something like this in my shower, to provide direct warmth and a just a little UV light to keep the skin from looking so pasty. Plus the light that leaks into the visible spectrum just makes your day feel a bit brighter. Considering the long, dark, glum winters here in the Netherlands, it is not surprising a couple of Dutch guys created the concept: Check out their interesting background story.
It creates sort of an ecological trade-off: I have a feeling that low-flow shower heads are far more palatable if you feel the soothing warmth projected from these units from the minute you step into the shower. But that requires a lot of wattage to save a few litres of water.
Recessed in-wall units seem to require venting (presumably to cool the ~2k watts). They also make an open air corner mounted unit: