One more thing to ask, which I only realized once I start to think through how I am going to use NifTI-2: Any chance of requiring all unused field and empty byte after the string termination character for the field to be set to \0?

Right now with NifTI-1 I have to use nifti_tool -diff to  compare two headers, because it ignore rubbish that might be present in unused field or empty space after string termination character. it would be useful to be able to use standard UNIX diff as well. Furthermore, the proposal works better with revision control system: the difference in unused field or space after termination character will cause them to treat two identical nifti files (in information) as different.