Yes, I want FE-BE protocol-level batch inserts/updates/deletes, too. I was just about to start thinking of how to implement it because of recent user question in pgsql-odbc. The OP uses Microsoft SQL Server Integration Service (SSIS) to migrate data to PostgreSQL. He asked for a method to speed up multi-row inserts, because the ODBC's multi-row insert API takes as long a time as when performing single-row inserts separately. This may prevent the migration to PostgreSQL.
Well, there's FE/BE level batching/pipelining already. Just no access to it from libpq.