are you sure your zero is dead, or could it be a fubar'd internal sd?
i too had sadly resigned that my GCW was toast, but wanted to salvage the internal sd to use with my wii (as my micro sd collection is running low).
but when i plugged the internal sd to my pc it wouldnt read it at all, and got physically super-duper hot. it is now much better suited for cooking tiny eggs and minibacon on rather than hold information =P
anyhow, to make a boring story long, i found a 2gig and used
snesfans windows tool to flash the firmware onto it.
it done did worked, and now my gcw lives again! =D