Or accompany every text file with another manifest file with all sorts of metadata in it (record count, crc, what you have it). Even the file name can have metadata embedded and separated with periods, like filename.<tag for date, etc>.<metadata, e.g. checksum>.txt and then get the files by name, tag and extension and parse out the metadata.
The question is does a MSFT text file store metadata and if so is it accessible by DTS tools: VBScript, PerlScript. I'd think in 2005 one could use CLR.