is there anyway to have rockbox announce the name of each artist/track?
No. You can make it voice filenames in the file browser, but that's kinda different.
PSS And because I can not try it yet - perhaps it's a bad idea in general? would get annoying really fast?
Yes. There are a few corner cases where this might be useful, but at least I think such a feature would be annoying pretty fast. There has been some discussion about something like that in the past, search the forums.