1) It appears that there is already a blog out there which posts all the ways Google screws up... and how to do stuff with Google. http://googlesystem.blogspot.com/2008/06/gmails-limitations-for-sending-messages.html
2) As a very early adopter of Gmail (8/6/4; 536,352 emails kept) I have been frustrated before by the lack of information the system gives.
Gmail has finally fessed up to a few of the limitations! See, http://groups.google.com/group/hosted-setup/browse_thread/thread/433297e19728b875 and http://mail.google.com/support/bin/answer.py?answer=22839.
However, it took far too long for Google to admit to these limitations. For example, http://mail.google.com/support/bin/answer.py?hl=en&answer=8770, wasn't available until recently... and the error upon trying to send, say 10 mp3 files from your home computer to your laptop via gmail, told you that you had a timeout... not that the mystery (at the time) limit was exceeded.
Glad the information is finally documented....