I bought an Tenere tank on Ebay and tried to make it fit but The XTZ frame doesn't have anything in common with the XTR frame so it wont fit.

Instead I went for the Gillimototank and I am happy with my choice, bolt on and takes about an hour to install. For extra fuel I've fitted Fehling crashbars which I've mounted Ortlieb 11 litre bicyclebags on where a 5 litre sparecan fits perfectly, in total 32 liters of fuel.