Every famous person I've ever dreamed this way about has been a singer/musician. David Bowie, Thom Yorke, John Lennon, Bjork, Ewan McGregor (if you'd seen Moulin Rouge as much as I have, you'd think he was a singer/musician too.), etc.
Maybe these people speak to me on a deeper level because of the amazing song writing and vocal talents I'm so familiar with. They make me feel more connected to the song and the performer, even when that may only be marginally accurate if at all. Maybe, just maybe, I some how really tapped in somewhere, like some weird cross between Waking Life and Being John Malchovich.
Or, maybe it just further proves my thing for musicians.