Market Data Definition Language (MDDL)
Google
The Financial Information Services Division of the Software & Information Industry Association
MDDL Samples
Static Equity Examples

Derived from a prototype demonstration, these files have been updated to be compatible with MDDL 2.0-beta and will validate against this schema. As of 01 February 2003, they still do not have fully described data consistent with "best-practice" (which is being corrected).