It would be nice to do by overloading print() and println() rather than adding functions with different names. If it's not possible to distinguish progmem strings by types, perhaps we could wrap them in a simple class? For example:
where F() is a class constructor (or a macro that substitutes in a class constructor).
I believe Mikal Hart did some work along these lines.
Patches on the Google Code issue list would be the best way to move this forward: http://code.google.com/p/arduino/issues/list