I'm from Jotel. With Janus Software we have developed Compiere port for Fyracle which is Oracle mode Firebird. It was quite functional and required juest very few modifications of code (none of which would break Oracle mode - but Compiere was reluctant to contributions)
By the way it would be much more elegant do detect new DB providers than hardcode them into code. The simple and good method is ServiceLoader which looks for META-INF/Services in jar. Then if db jar provider is in classpath it would detect it.
Could I get access to svn tree ? I have also some annoying bug fixes like combo box right click menu for non Compiere l&f, select as type for combobox , repaint bug fixes for Linux (very annoying on remote X) etc.