I really like the looks of this Halo 4" shower light i saw at Home Depot. It's available with a white/satin or dark bronze trim ring and has a clear prismatic glass lens that lets alot of light through and disperses it well without leaving too much glare. The trim is quite deep, includes a reflector for stardard shape (A19) light bulbs, and is IC rated. Not sure which housing works with it, haven't looked it up, but they probably have a remodeler kit available - but are any remodeler housings IC rated? If not, you may need to cut out a square of drywall between the ceiling joists, install a new-construction IC housing, and replace and refinish the drywall panel (now with a round cutout for the lamp). This trim also should work great with LED light bulbs designed to retrofit incandescent fixtures - these are available for $10-$12 and many of them are "snow cones" that send all their light out from the top of the bulb - perfect since the bulb faces downward in this fixture. You do need to verify that the bulb you want to use doesn't have a warning on it that it can't be used in completely enclosed fixtures though. I think this bulb sold at HD for $9.97 (under their EcoSmart brand) doesn't have such a warning; at least it doesn't in the online specs). CFLs and halogens are also options with this fixture.

Here is a link that might be useful: Halo 4