Hey I moved to Munich this year and am investigating the DH nearby at the moment. There are some nice flat trails along the Isar which, although a DH bike would be complete overkill, could probably be ridden as there is basically no uphill pedalling involved. There are a few bits where people have built up the trails to make drops etc or some steep rooty sections, you just need to find them and link them together. Nearby there are lots of bike parks and lift served riding. I have only been to Samerberg so far which isn't really DH, more like lift served trail riding but fun for a day out and only an hour by car from Munich. If you don't have a car you can get the train to Lenggries, not been there though yet. If you have a car there are a ton of bike parks really nearby in Austria, Leogang and Saalbach look biggest but also Schladming (Planai), Wagrain, Hopfgarten then you have Italy and Switzerland as well as well as the more northern parks like Winterberg.
Aye, what she said up there Theres LOTS of uplift options that are well worth checking out, and don't forget Czech republic too! Spicak is awesome (and cheap)!
Get onto the local expat website 'Toytown', theres a group of us that go regularly just hit us up when you're settled if you fancy joining.
You don't have to go very far. Your best options from Munich are Samerberg and Lenggries. Then further is Leogang and Bischofsmais. Directly in the city there is nothing apart from the Isar Trails which is more XC than DH.
Just back from a week in saalbach and Schladming. Saalbach was great a lot of trails and nice variety and I found the bottom section of the DH course really tough so nice to have something to work at Schladming was a lot of fun as well although really only one trail as a lot of the blue was on fireroads and easier than the Saalbach DH as well.