Well, thanks to the new EvoX Dashboard, you can read/write to the memory cards (remember the news post? EvoX Dash maps drive letters to each of the eight slots for mem cards). Far as I can gather, no one has reliably copied games to a 'memory card', but the sparce reports I've heard aren't good (it goes slow, cuts out, etc). Hell, people at XboxHacker.net have been doing this for about a month and a half now (but until recently, just as a really big memory card to store the game saves). Before you try this trick, though, make sure nothing important is on the drive, connect it to one of the controller ports, power on the XBox, and go to the original Dashboard. Upon this happening, it recognizes the HDD as an unformatted mem card, and promptly formats it as an XBox memory card (probably with the XDFS filesystem, but I'm just guessing).
Try it out. Personally, I'm buying a 10GB IDE Drive, getting the IDE->USB converter, and testing it out. I'm hoping the unreliable performance is due to power issues (the USB port can't deliver enough power, the HDD powers off for a second or so, whilst aborting whatever file transfer you're performing with it). I'm hoping the external power supply for the USB drive solves the issues (the IDE->USB converter makes you plug the power plug into an outlet.... yay!).
In case you want the link to one of the many IDE->USB converters, check this out:
http://www.macally.c...ce/ca805uh.htmlor you can simply do what I just did and type into Google "IDE to USB". =-)