The internet radio stations I listen to for programming music require each mix (song) to be between 45 and 90 minutes, not fade or do other distracting effects, and a couple other basic rules that make it quite good for programming.
I have found some decent web stations, but for the most part I just rip hundreds of tracks from dozens of stations at a time and pluck out the couple good songs and then repeat.
I'll get back to you on that.