I emailed MUC cabin lost & found (thanks Oliver for the link), and I also sent a similar message (with details on the exchange in the lounge, questions about potential other lost & found departments at the aircraft's next destination, etc) to customer service.
MUC responded with a nice but negative message (i.e. nothing turned up). I guess it's about time I stop pestering them.
I also got this just now from CS, which makes me want to kick someone in the nether regions:
Dear Mr. martona,
Thank you for contacting the Lufthansa Internet Service Center.
To inquire about items left on a Lufthansa aircraft which may have been returned to the lost and found department, please contact our Baggage Call Center directly at (877) 234-3449. Our staff in this department has computer access to information about missing items.
We look forward to serving you, online and in flight. Thank you for choosing Lufthansa.
PLEASE NOTE: This is a one time generated message. Replies will be deleted.
I rang the number in the email. I wasn't expecting much, and I wasn't disappointed. They only deal with checked luggage, and the most they could do for me was give me the MUC lost & found number, which is of course still in my call history.
So chalk up another one for LH CS.
That last sentence is a very nice touch. No further conversation to be had on the topic I guess.
I'd totally go on a rage bender and write another message to CS just to make myself feel better (I'm sure no other good would come of it) but life's too short. Moving on from the issue. Kind of makes me want to move on from LH as well, a bit - see who would treat me with a bit more palpable illusion of being a valued customer in exchange for 16 TATL F tickets per year...