Worse Case: If the characters are continuous, back to back and with no
   pattern (and first character unknown), ahhhhhh ---- what
   in the world are you going to do with this anyway (just
   kidding)?  If this is the case, it's rather difficult to get in sync
   and determine the baud rate (data better not be critical!).

I suppose in that case you have to collect a second or so of data, run a FFT
and select the lowest frequency :^)