Is it possible to export a QGIS project to Mapnik xml?
I'm using QGIS 2.4 and Quantumnik does not seem to work with that version.
From what I know it is not possible because the Quantumnik plugin is supported until version 1.8. In that case I have seen that the export function works but you must paying attention to use the "old symbology" option for the layers styles.