A paper on "A Dynamic State-Space Model of Coded Political Texts" has been published as advance access article in Political Analysis. Accompanying this article, there is a data set with positions of parties in the economic and social policy spaces, reconstructed from Comparative Manifestos Project data using the method in the article. The data set is available from the Political Analysis dataverse. I will make a more extensive data set, suitable for multiple imputations and the like, available on my website in the near future. Here is a picture that shows what this method can do:

Positions of the Labour Party and the Conservative Party of the UK in 1964