vu sur www.gp32x.com =>
http://www.gp32x.com/board/index.php?act=ST&f=41&t=21707
http://www.gp2x.co.kr/support/support_faq_...&page=1&part=01
This is the interesting part. This section talks about the USB Host. And why they decided not to include it. It's because they consider it a portable device, so if they included a host port, it would require the device to be plugged into an external power device.
They go on to say, that they are planning a new device that will have an internal large lithium battery, powerful enough to run USB devices without an external power device.