[gonzotek]

Even if the drive was good, is there any way to get the data without using the drive in the Tivo unit? Even if we do that, is there a way to get Tivo to list everything that has thumbs-up? I do not know how to do that even in the Tivo UI.

I assume not, if it is true that the data is encrypted and can only be decrypted by hardware in the Tivo unit.

Tivo could provide a way to get the thumbs data in XML format in the same manner as the Now Playing data. The Wishlist data would also be useful. As far as I know the only reason they do not is because they do not want to. They also could provide a way for the Tivo to remember everything that has previously been recorded; movies at least. Show episodes would be more complicated but movies would be easy enough to store. Data such as that could be stored in a "cloud" somewhere.

There is simply no known way to extract the data you seek, except visually on the Thumb Ratings screen of a working TiVo.

Since the dawn of the TivoToGo feature (when they first introduced the xml web interface), we've been asking for additional data to be shared. Thumbs, wishlist, todo, and history have all been requested previously and we have not received any indication from TiVo that there will ever be more data available. One other possible (if unlikely) route to this data is via the newer API the TiVo remote apps for iOS and Android use:
http://www.tivocommunity.com/tivo-vb/showthread.php?t=462980
I suggest reading through that thread(it starts to get interesting around post 54 or so) and possibly asking there if anyone has an ideas.