Per the Service Products fiche, for the hydraulic fluid, the only other listing is Aral Vitamol ZH-M, from Aral Lubricants GmbH, Bochum (Germany?). On the label of the MB stuff, below the barcode, it is printed "10/99 AAB made in Germany". I believe the "AAB" is an abreviation, the first "A" for Aral, the "B" for Bochum. So in my opinion, on this particular product, either buy it from MB in their container, or get it from the manufacturer who makes it from MB, either way it's coming from Germany. I wish I could answer Bigshot's question on if there is anything domestic and cheap that can be substituted, but there is nothing MB is recommending.
I also looked up to see what the deal is on the 722.6 trans fluid, it is a very similar story. In the Service Products fiche, the only alternative to the MB part number is Shell ATF 3403-M115 from Deutsche Shell AG Hamburg (Germany). Again, on the label below the barcode on the MB stuff is noted "11/99 DSH made in Germany". On this it's easier to decide that the "DSH" must be the abbreviation for Deutsche Shell Hamburg. So it's in the MB bottle, but it is this particular ATF from Shell Oil in Germany, I believe it is a synthetic, although the instructor when I went to school for 722.6 didn't come right out and say that it is.