Not in the open-source version, no. It is possible to do (we have done it for Datical DB) but as far as I know no one has added that ability to Liquibase itself. Datical has added the ability to export stored procedures, Oracle packages, and many other features. Currently these are all proprietary to our product.
Steve Donie
Principal Software Engineer
Datical, Inc. http://www.datical.com/