@ Cutting NASA's apron strings?
Not in the next few years, and not with the $500 million (money well spent) NASA has awarded under COTS hoping to privatise launches to the ISS. Why would SpaceX not want a customer like NASA?
www.spacex.com/press.php?page=20081103 refers to Dragon docking with the ISS in 2010.
They're clearly looking far beyond supporting the ISS. Delivering people and cargo to the Bigelow inflatable habitats for a start. And what about beyond earth orbit? I wouldn't be surprised if they beat NASA back to the Moon.
@Non-reusable space planes...
"Reusable space planes are, without exception, much more expensive than non-reusable."
Are they? The Shuttle is the only one so far and it's a 40 year old design. And many of its problems are due to its size. I'm sure that a smaller version using today's technology would be a far different animal.