There's no technical reason why it couldn't be added, but to avoid "the death of a thousand cuts" we tend to shy away from complex niche things that a tiny majority of people will ever use. That said, there will be a "feature requests" voting capability on the website soon where you can deposit the request and if it became a highly voted for feature, we'd reconsider.
NB: vpeter created a TrueCrypt addon for OE in the past which can probably be resurected for LE (or it still just works) or this is something that you or someone in the community could package into a similar add-on format. We welcome public add-on contributions, as long as people maintain them.