We would love to add support for other databases, but we need help from someone experienced with those databases. If you have an interest in joining the development team in order to build SQL generation for other databases, please let me know and I will get you started.
There may, however, be technical obstacles from a database feature point of view. There is, for example, no support for table elimination in MySQL, which means all features cannot be ported. Both DB2 and PostgreSQL have table elimination, but I am not sure if other features are missing, such as the ability to create parametrized views, clustered indexes (or index organized tables), foreign keys, column statistics, etc...
Noone is currently working on Oracle support that I am aware of. The limited support in the test version is all there is at the moment. There are a couple of active PostgreSQL projects though, that can be found as forks/branches on github.