I am not an expert in coffee, but if you widen your search parameters a bit, you might find what you are looking for in papers dealing with the sustainability of different farming systems. Some examples can be found here:

http://www.sciencedirect.com/science/article/pii/S0167880901003516

http://pubs.aic.ca/doi/abs/10.4141/P98-110

http://www.sciencedirect.com/science/article/pii/S0308521X98000523

http://link.springer.com/chapter/10.1007/978-90-481-2666-8_44

Muchas gracias Michael 

Check out this

www.onlinelibrary.wiley.com/

Time Series Analysis Univariate And Multivariate Methods ；

Applied Multivariate Methods；Applied multivariate methods for data analysts Duxbury Press；The Second Edition of Alvin Rencher's Methods of Multivariate Analysis 

Hey Carlos.

I think you are on to something very interesting there. 

Multivariate methods application on sustainability of (in particular) coffee farms, is an interesting way to tacle the problem of sustainability of the farms.

The trick could be, how you quantify the various factors that affect the sustainability of the farms. If you can quantify them then you can apply multivariate methods to solve the issue of sustainability.

If quantification of the factors is as problematic as I imagine it to be, I wonder if other methods such as fuzzy logic or Artificial Neural networks could be of much help. 

Goodluck

Gracias 

Try adapting my approach to assessing watersheds.  Different metrics should work for coffee farms.  

https://www.researchgate.net/profile/Albert_Smith5

Here are some ways to look at determinants of innovation and sustainability. Uses mangoes and rice as commodity cases.

Article Learning and Innovation Competence in Agricultural and Rural...

Article Critical Systems of Learning and Innovation Competence for A...

This might be useful, if not exactly what you requested:

Méndez, V. E., Shapiro, E. N., & Gilbert, G. S. (2009). Cooperative management and its effects on shade tree diversity, soil properties and ecosystem services of coffee plantations in western El Salvador. Agroforestry Systems, 76(1), 111–126. doi:10.1007/s10457-009-9220-3

It will depend how you're defining "sustainability".