Yes, that's exactly what I would have expected to happen, with the // as a prime candidate for that separator.
Big-endian domain names would have been very nice to have though, if only because it would have been a lot more orderly than the current jumble.
Big-endian for the 'major' components and the path name, little-endian for the host portion seems a bit weird.
mail:/com/domain/hostname//username
Would look strange though...
People would just end up using a different separator after the DNS part, and you'd be back where you started (just with big-endian domain names).