In DIP packages? You'll have to go WAY back, technology wise. Jameco still claims to
sell 64k, 256k, and 1M bit DRAM chips in DIP packages:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&productId=42219
I don't recall if chips bigger than 1Mbit were offered in DIPs.