Partha said
I'm trying to create a number of matrices in Mata ordered, e.g., x1, x2,
..., x7. I'd like to set up a loop to create these. 
This question was asked and answered earlier this month: please see the Statalist archives. The answer (as it would be in C) is a matrix of pointers.
Kit Baum, Boston College Economics
http://ideas.repec.org/e/pba1.html
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/