VML* is a language for generating product models in model-driven software product lines. More precisely, VML* is itself a product line of such languages, as the first step is generating a VML* language specific to your modelling language of choice. More information can be found in our respective papers:

Steffen Zschaler, Pablo Sánchez, Joao Santos, Mauricio Alférez, Awais Rashid, Lidia Fuentes, Ana Moreira, Joao Araujo, and Uirá Kulesza: VML* -- A Family of Languages for Variability Management in Software Product Lines. Mark van den Brand, Dragan Gasevic, and Jeff Gray (eds.): Software Language Engineering, 2nd Int'l Conf. (SLE 2009), Revised Selected Papers. LNCS 5969, Springer, 2010. [pdf (The original publication is available at www.springerlink.com.)][slides][http][additional material]

Florian Heidenreich, Pablo Sanchez, Joao Santos, Steffen Zschaler, Mauricio Alferez, Joao Araujo, Lidia Fuentes, Uira Kulesza, Ana Moreira, and Awais Rashid: Relating Feature Models to Other Models of a Software Product Line: A Comparative Study of FeatureMapper and VML*. Shmuel Katz, Joerg Kienzle (ed): Transactions on Aspect-Oriented Software Development VII, Special Issue on A Common Case Study for Aspect-Oriented Modeling. LNCS 6210, pp. 69--114, Springer, 2010. [pdf ((c) Springer Verlag)][http][additional material]

These sources are the original sources. In particular, they have not been updated to work with the newest version of XText etc. They will likely need a lot of work to make them work with the newest versions of existing frameworks, but, unfortunately, I don't foresee having the time required in the near future. Feel free to fork and improve and please share back with a pull request.