There was talk of making the MK1's USB port emulate one of those USB-ethernet adapters (kind of the reverse of plugging a USB-ethernet adapter into the player), but no one has yet tackled this one.
There's a code dump of that project in the Hijack source tree (not compiled into the binaries by default, though). Apparently it is almost usable as-is, but not quite. Just needs a bit more TLC.
I don't remember whether it was for Mk1 or Mk2(a) players, though -- unless they have identical USB controllers (?).
If you have some software skills and fancy a bit of poking into the kernel driver, you could probably complete it in a day or two.
Cheers