We also want to try out to use the Samsung SCX-4200 printer with a hacked Western Digital Mybook World Edition 500GB device. The simple NAS runs Linux and we can use the USB host to connect to the printer and use CUPS to share the printing function. However, it seems that sometimes the printer will stop functioning. My brother-in-law bought this Mybook World in the Comex show recently held in Suntec City. He did quite some research and successfully got the hacked version work nicely as a file/P2P server. But the printer server function is still not so good. Sometime it works. Sometimes it does not.
I tried to downgrade the printer to use USB 1.1 Full Speed by inserting the USB 1.1 hub in-between the host port of Mybook World and SCX-4200 but that does not help too much.