You can get a SPI USB Bundle for $29 here http://www.diygadget.com/xbox-360-usb-spi-jtag-utility-bundle.html but why not make your own lpt cable for like $4? it still reads NAND just slower.
Well I guess the spi usb kit would be your best bet.... It needs it's own firmware I believe but that shouldn't be hard to find.
Sorry I thought you meant a nand reader. Also if you plan to have it inorder to have different Nands for different game reigons, it became obsolete a while ago, since they released a reigon free patch for freeboot consoles. It got included in the dashlaunch plugin.
Yeah Nand-X is the fastest, but the Xbox Experts, and DIYGADGET's are the same, and they do not offer dual nand, but they preform the same task. Hawk