This is amazing, and in fact it's exactly what we needed for a paper we are about to start writing (Indifference Merv, take notice):
The G-Econ research project is devoted to developing a geophysically based data set on economic activity for the world. The current data set (GEcon 1.3) is now publicly available and covers "gross cell product" for all regions for 1990, which includes 27,500 terrestrial observations. The basic metric is the regional equivalent of gross domestic product.
Here's the project's homepage, thanks to Netsmith for the pointer.
This paper (free access) is particularly interesting - it's also short and very readable:
Three applications of the data are investigated. First, the puzzling 'climate-output reversal' is detected, whereby the relationship between temperature and output is negative when measured on a per capita basis and strongly positive on a per area basis. Second, the database allows better resolution of the impact of geographic attributes on African poverty, finding geography is an important source of income differences relative to high-income regions. Finally, we use the G-Econ data to provide estimates of the economic impact of greenhouse warming, with larger estimates of warming damages than past studies.