I would think that any dealer or ind. shop should have the hose. Mine were like yours. I just went to the shop that I bought the car from. He just gave me about 2 feet of hose. Which was enough to go from injector to injector. He told me it is normally $1.50 a foot, but he just handed it to me. What I got was rubber with a braided cloth covering. It says "made in Germany" on it. I don't know what "mm" size it is.
1980 MB 300SD
1999 VW Passat Wagon