tuxduino:
I want the user to be able to specify a size. At compile time. Dynamic allocation would mean grow the array as elements are add()ed. String is telling us that kind of functionality is not without problems
A point of note You can't do that with a #define and the Arduino IDE as you intimated earlier. Only the code in your sketch sees the #define, the library is different compilation unit, and does not see it with the standard arduino make process. (Unless of course, you ask them to inline your code in their .ino or something.)
!c