Thanks for the replies. Since I'm new here it is possibly worth mentioning that privacy and security are interests of mine, so I frequently think in those terms. FWIW, I am familiar with Truecrypt and other tools for creating encrypted drives and containers in which files can be stored. I particularly like encrypted file containers for storing sensitive records. The well known problem with that, of course, is that the OS and applications can effectively copy sensitive data from an encrypted store and write it to a less or not at all secured media. It's one thing if an app creates and leaves a temporary copy of such a file in a known directly where it can be subsequently selected for wiping. It is another thing for an app to make a temporary copy of a such a file and then delete it, leaving nothing for the user to select for wiping. Coupled with other issues such as storage devices internally implementing wear leveling and filesystems being in the best position to know what has to be over-written in order to purge sensitive data, this makes secure destruction something that requires some OS/device support.
That BCWipe Transparent Wiping capability is interesting and I'm looking into it. Ultimately, I will likely again utilize FDE as an outer layer of protection. However, even when using that I would welcome any improvements in the ability to overwrite destroy rather than simply delete file data.