I just gave a try to the BufferedFileStream. As usual, code is MIT. Implementation is rough, readOnly, partial (no support for basicNext crap & al), untested (certainly has bugs). Early timing experiments have shown a 5x to 7x speed up on [stream nextLine] and [stream next] micro benchmarks See class comment of attachment
Reminder: This bench is versus StandardFileStream. StandardFileStream is the "fast" version, CrLf anf MultiByte are far worse! This still let some more room...
Integrating and testing a read/write version is a lot harder than this experiment, but we should really do it.
Nicolas