Still you should consider derive it from the print Class so the user gets access to functions as print(float, 3) etc.(make it #ifdef configurable ?)
In another thread I replaced the magic numbers of soft serial with formulas allowing "all" baud rates. - http://forum.arduino.cc/index.php?topic=138497.0 - should be possible here too. The added value is that you can easily adjust baud rates to mismatches in clocks or systems that have lots of interrupts.
FInally, can we expect a stripped read-only serial too?