Hi Chris,
"There sure must be some way to access the older backup! That's what backups are for, aren't they?"
Unless something has changed very recently in the new firmware updates, this condition remains. Hopefully, some other users may have figured out a work around on this, but I can't find anything on the boards about this. Two local "genius" types in the DFW area unfortunately don't have answers either.
On another issue, they said it couldn't be done, but I did figure out a way to access backups from another computer when sharing was already enabled and setup on the network. See this recent post:
http://discussions.apple.com/thread.jspa?messageID=9750502�
Hope this might help.