I don't remember seeing the mega big toblerone in MUC's duty free shop. You could email them :
http://www.munich-airport.de/en/cons...2_05/index.jsp
Note that you get M&M points for your purchases in MUC.
ARN will be more expensive than MUC. MUC sweets are almost the german retail price. You might want to check retail prices for that stuff in the US first though. The sweets in the duty free store are really not 'duty free'. The benifts only come if you buy booze and smokes (even cigarettes are cheaper than german duty free in North Carolina

) With the current downturn toblerone is surely cheaper in US.
There is a special screening for US pax in MUC after the duty free store. Chocolates are permitted on board, so You should face no difficulty. As far as space on board is concerned, you may have to settle with storing it under the seat in front of you.