What you're looking for is what's call an insulation contact (IC) retrofit housing. Halo (Cooper Lighting) makes them but most people use some kind of flood light in recessed cans, so I don't know if you could use an ordinary compact fluorescent lamp with one of the 5" models. Halo does make an IC retrofit can with a built in fluorescent ballast and you'd just plug in the lamp.

If you can't find what you want at a big box store, you'll need to try a electrical or lighting supply house.

You can usually find someone online that will sell you the HALO stuff for less than the big box by about 20%, of course you usually end up paying for shipping so it often comes out as a price wash.

As mike says, 5" IC housings are available in both regular incandescent or designed for non-retrofit CF bulbs. In fact, there are some straight downlights I've seen that are LED fixtures.

Thanks guys, this looks like what I need. If the can is not particularly tall, I thought I would install it so that it pushes against the paper vapor barrier of the insulation batts above. It that more of a fire hazard or is it better to cut through the paper and cut a 'hole' in the insulation roll?

An IC fixture is allowed to touch the paper, wood framing, the insulation, or other structure.

Lightolier 1004ICR

http://www.lightolier.com/MKACatpdfs/1004ICR.PDF
http://www.lightolier.com/products/index.jsp?CATREL_ID=20475&BLK=N&CAT_ID=24369