I had a .net process called DataAssimilator that did such a function for a prior company. The C# program only imported into a dynamically created or a pre-existing staging table and then had an optional parameter called 'ImportSQL', usually a stored procedure. A DTS/SSIS package could use it too. I never used DTS/SSIS itself to do dyamic staging imports. DataAssimilator was good for SHRM org data imports (no standardized iterim-format; each needed its own assimilation proc) and client bulk-imports (had standardized interim format; all shared one assimilation proc) which often needed multiple-table upserts but little scrubbing.