How many days? And is it a riding trip (higher miles and technical roads) or a holiday trip (wife along, lots of photo's and cafes), or something in between?
Depending on the answer, something like the below could suit you - some of the best roads in that neck of the woods. I was figuring 6 days for this trip. 7 days would be nicer for photo's and relaxing.
A lot of Germany is really, really dull riding. Austria is better, but a fair old hike to get there, and better riding down in Switzerland/Italy, plus the cops in Austria don't show much of a sense of humour... The above route uses Germany for the National Forest (which you've done and is excellent - just more and more cops there so watch it!) and other than that just utilises their motorways to make up distance, plus takes in the Nurburgring which is a must (just check it is open for visitors the day you plan to pass through!!). The Luxembourg region - Vianden and the forests is wonderful, we go there most years.
I have loads of options, and can share the waypoint files with you.
2011 KTM Adventure 990 R, with loads of extras and farkles
-- silk metallic with comfort package (sport wheels, heated grips, on board computer with oil warning, sport fairing, LED white indicators), alarm, gear shift assistant --
-- Hepco rear rack, R&G protectors all over, Akrapovic full system, Evoluzione dual air-filters, 1/4 turn quick action throttle, disabled full load stop actuator, a permanent grin --