From the looks of the code and the rest of the discussion, they are emulating the plugin and plugout of USB devices in a HUB. Not sure if the PSP has the HUB USB Capabilities, but I am sure one day something will happen. Would be a nice convert way of doing it as well.
Wonder if there is some sales rep @ Amtel (think they supply the chip) wondering why the demand for his chip has gone through the roof. Somebody there is going to make a mint this fall, and I was one of the lucky ones to get one of the last 4 from an Australian supplier advertising on the web.