Where to find GIANDUJA?!
This confection, like nutella but 100 times richer, is probably the best thing that has ever touched my lips...but I don't want to buy it online because shipping is horrendous :(
Are there any italian grocery stores (or any grocery stores, period) that sell it around DC?
I'm pretty sure I've seen it at the Italian Store on Lee Hwy. in Arlington. You may also want to try Cornucopia in Bethesda. It's a small Italian deli/grocery and they have a lot of imported products.
Whole foods often has one from Rapunzeland maybe another brand as well. Dean & Delucca would be another spot I have seen it.
Try Rodman's. They have lots of European goods. I go to the one by the Friendship Heights metro but I think there is one in Rockville.
Go to Biagio Fine Chocolate (18th St between T and U). I am pretty sure they have the good stuff there...