I haven't actually tried that, but I have tried it with the "data" USB connected to me pc (in the vain hope that the mass storage mode would kick in, and I could remove the books I just added - didn't happen).
The device was fully charged when I had to do this, twice, last night.
Is it my understanding, that on the Touch, you can get back to the library/home screen after restarting from a "Processing Content" stuck screen, somehow? (presumably, sans the new books that didn't get added?)
It wouldn't bother me so much if this was possible, as at least you were back to where you were before you added the books. Right now, I'm back to where I was when I bought the Glo from the shop... :@ (makes putting new books on, like I said, a bit like playing Russian Roulette
)
Thanks,
Matt.