The Zen uses a 2.5” hard disk. We’re talking about 1.8” hard disks. I suspect they should be available later this year or next year in better quantities. ALso, you have to imagine that the initial prices will be expensive since they’re the only ones making it right now at that size.
It took a little bit before 40GB drives were available at decent prices in retail channels, and I’d expect a wait on the 60GB ones as well. As I understand it, Toshiba sells these drives almost as fast as they can crank them out, and Apple uses a lot of the supply with the iPod, in addition to Toshiba using it in their Gigabeat player.