@gcraig After @tobias.koetter gave the hint I toyed around again with DuckDb and created these examples. Some SQL code needs dome adaption but in general it would work. Tested to insert a Parquet file and auto-detect a CSV structure. But to be honest the handling is not as straight forward with KNIME as with H2 and SQLite - but indeed you could use DuckDB and KNIME 
The driver can be found also here:
