Wade Cole sent me a link to a useful data source, the KOF index of globalization: http://globalization.kof.ethz.ch/
They create 3 measures of globalization, reflecting economic (trade, FDI, barriers), social (communication), and political (embassies, international orgs, treaties) dimensions.
They rely in standard measures that are pretty familiar. A full list of the measures (and weights used to create the indices) can be found here: http://globalization.kof.ethz.ch/static/pdf/variables_2010.pdf
Coverage looks pretty solid — from 1970 to the present. Overall, worth checking out.