Update October 2016
Good news day! I have found them, hidden away:
https://www.adac.de/reise_freizeit/motorrad/
Scroll down and click on Tourenkarten, mehr. Then click on the PDF links.
I'm not sure whether these are the same maps, different, updated or what. But download them quick before they vanish again! They look a little different (in style at least) but look good either way. Worry not that they have a picture of a car on the front; they are free! *
edit
There are 13 PDF's in all, numbered oddly 1 to 14. Whether one is missing or (because of superstition) ADAC missed out 13 or if they simply misnumbered one along the way I have no idea and I'm in no great hurry to find out. As before, the PDF's download really well into iBook and display well on a big iPad.
Have fun, you can't break it.
Richard
Sample PDF map, converted into a jpeg:
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Edit:
* I have now looked at the Swiss and the Trentino maps, just as as a sample. They look much the same routes as the original version. Use with confidence.