[Haleth]

Without an addon, no, but you could have a shot at changing these:

KEY_NUMPAD0 = "Num Pad 0";
KEY_NUMPAD1 = "Num Pad 1";
KEY_NUMPAD2 = "Num Pad 2";
KEY_NUMPAD3 = "Num Pad 3";
KEY_NUMPAD4 = "Num Pad 4";
KEY_NUMPAD5 = "Num Pad 5";
KEY_NUMPAD6 = "Num Pad 6";
KEY_NUMPAD7 = "Num Pad 7";
KEY_NUMPAD8 = "Num Pad 8";
KEY_NUMPAD9 = "Num Pad 9";
KEY_NUMPADDECIMAL = "Num Pad .";
KEY_NUMPADDIVIDE = "Num Pad /";
KEY_NUMPADMINUS = "Num Pad -";
KEY_NUMPADMULTIPLY = "Num Pad *";
KEY_NUMPADPLUS = "Num Pad +";

Just replace them with whatever you like and put it in an addon. It's possible that it causes taint though.

Or if you don't want an addon for some reason, put it in a macro starting with /script.