There are LED cans available. And they're rather attractive once you look at all the specs and compare the price to building your own can / housing / bulb / ring / etc. I just used five 4" LED cans in my library project.
Home Depot sells Lithonia Light brand in 3" ($50 - 7.5w, 345 lum), 4" ($55 - 8.7w, 400 lum) and 5" ($60 - 15w, 600 lum) models. All sizes are dimmable to 15% before blinking, they're IC-rated, airtight, and rated for damp locations. They use a special connector, not a bulb socket, so you couldn't install incadescenct / halogen in them even in you wanted to, meaning the wattages you see above are probably their "max rated", at least as far as I can tell. I'm not a code jockey, so that requires verification.
I compared using CFLs w/ a non-IC rated can installed in an IC-rated housing to get a similar effect and came out saving only about $7 per can once I figured in the ring, appropriate bulb, etc. It wasn't worth it for me to build my own set. Plus, these LED cans are a whole lot smaller than a big, 'ol IC-rated housing that I'd have to install between the ceiling joists, I didn't have to take a big piece of drywall down to install them, they can be installed from below (my situation was special and required attic access because of some design features I went with in the library unit) and they come with the legs to retrofit onto existing drywall. The only downside was that I wanted a gimbal-type swivel like you can get with the Halogens and that wasn't available, but I haven't looked back. I figure the $7 will earn itself back in energy savings in a year or two.
Hope that helps. Throwing a few extra $$ at the can could save a couple hours of electrician labor.