Saw this on DPR, all metal construction, dust and splash proof.
http://www.dpreview.com/news/8715144802/hands-on-with-new-panasonic-leica-summilux-12mm-f1-4-asph
http://www.dpreview.com/news/8715144802/hands-on-with-new-panasonic-leica-summilux-12mm-f1-4-asph