Cellit and thermocellit are just 2 of the seemingly endless types of clay tile products available in Spain. These are typically used as load bearing walls and they DO require mortar and installation. These are fairly common construction solutions and in my view are not terribly green, but not bad, either. Thermocellit provides a decent, but not great amount of insulation.
Monocapa is a normal "stucco" type finish. The interior is usually finished with gypsum plaster. Channels for wire and plumbing are cut into the clay tiles.
I lived in a house with ±30cm solid masonry walls, single pane windows and no weatherstripping outside of BCN for a few years. A bit chilly in the winter....probably like living in an English castle but in a better climate.
If you want to really go green, think about doing a Passivhaus.
http://ec.europa.eu/energy/intellig...ive_on.pdfBruce