Technically, since QRP means 5 watts or less on CW and 10 watts or less on SSB, you could use a CB with 10 watts on SSB and be considered a QRP operator and not need a license. Some CBers make contacts worldwide running legal power of 12 watts SSB -- though usually not on the 40 legal channels -- but I don't think that's what you're talking about. I have to say, though, that I learned a lot about QRP operation -- setting up the station properly, maximizing the antenna efficiency, etc. -- before I ever became a Ham.