Did you know that you can generate playlist content in a random manner from iTunes?
Did you know that iTunes actually incorporates a Smart Shuffle randomizer to counteract this perceived un-randomness that users believe to be inherent with the iPod. It actually analyzes the random songs played and changes the likelihood of the user actually hearing the same songs, it does away with a sequential playback.
I use specific playlists where the music obviously isn't repeated.
But when I ask the iPod to shuffle everything, I get either the same artist, album, genre or song within a short period of time. It went through 5 of the same genre just the other day. And I have an even mix of everything on there. I just loaded more music on there, let's see if that helps.