I recently came up with a novel arbitrary-integer-length binary encoding called BLIP (binary large integer prefix), which also begat a novel binary container format (which of course can be of arbitrarily large size)

https://github.com/pmarreck/BLIP

Anyway, a protobuf-relevant excerpt from the README:

    "BLIP is 4x faster than LEB128/Protobuf for large value 
    encoding (1.3 vs 5.1 ns/op) because it writes raw LE 
    bytes with a single memcpy instead of shifting and 
    masking 7 bits at a time."

Among other (I think) interesting features, there's a reserved bit (but only if it makes sense, if the value is multibyte) for endianness, which would potentially solve that whole problem (which is also documented in the README)

I am not really advertising it so much as wondering if it's actually useful to others as I don't normally operate at this level (I'm an Elixir dev by trade, although I seem to be drifting towards much lower levels... Zig)