I'm sorry to throw a PhD dissertation at you. But I believe Food shortages and economic institutions in the Democratic Peoples' Republic of Korea addresses your concerns. From page 168 (179 on the freely viewable pdf). Addresses whether there was a famine using the accounts you have hinted at as well as UN figures, with comparison to official DPRK figures. It looks at the evidence we have for their production, their consumption of food aid, amost other things.
edit: The sources he's used that I've looked at are UNICEF, ROK figures (probably not what you wanted) and NGO figures like the KBSM below.
Some of the data used but not given can be found in Forced Migration and Mortality. The abstract is of interest but too long to post, here is some of it:
Buddhist Sharing Movement (KBSM) released a report on the North Korean food crisis based on interviews with North Korean migrants in China ... FIGURES HERE... “that the worst famine in human history is now transpiring in North Korea” (Korean Buddhist Sharing Movement, 1998).
Concerned by these accounts but unable to assess the reliability of their findings, a U.S. nongovernmental organization (NGO) active in North Korean humanitarian relief, Mercy Corps International, invited the Johns Hopkins School of Public Health to undertake its own study of North Korean migrants in China. In the past five years, significant numbers of North Koreans have been moving across the Chinese border in search of food for themselves and their families. It is estimated that between 50,000 and 150,000 North Koreans are staying temporarily in China...