I'm surprised that as technology advances we don't see more long songs. Back in the 60's and 70's you would have rock and jam bands do long song songs, that were far longer than the 3-5 minute radio spot. One of my favorites in this genre was the 27 minute version of Dazed And Confused by Led Zeppelin off The Song Remains The Same sound track. It was carefully timed to fit the whole side of a record.
With cd's it became possible to do a 60-70 minute track if you wanted to, and with mp3 the time limit expands to how ever much hard drive space you have.
This has me wondering what the longest song released by a mainstream artist in the last few years is. Is there anyone using the unlimited time constraints for music, or is it just wasted on hiding "hidden tracks"?