While it would be nice to have a format that meets all of Phil's expectations, I don't know how practical it would be for vendors to create and support such a format for what you would gain from such a standard. The biggest problem I've had in my 17 years in IT, is that the tools we use for ETL, in an attempt to become more powerfull or flexible, have actually made it harder to work with the formats we do have available.

CSV, tab, pipe symbol delimited files, or even fixed width files may not have metadata and may not support unicode, but are still frequently used because they are the lowwest common denominator, and will do for the vast majority of situations. However, thinking back to the early-mid 90's in my FoxPro days, it seemed you could read in and export out these text files, or even spreadsheets or other simple formats quite easily compared with trying to do the same thing in DTS with SQL Server, and is even more difficult in SSIS. The ETL tools are what is failing us and make our lives more difficult than it needs to be