Generic taxonomy-term template page

Simply use taxonomy-{taxonomy}.php.

Refer to the Template Hierarchy Codex entry regarding taxonomies.

WordPress will look for taxonomy template files in the following order:

  1. taxonomy-{taxonomy}-{term}.php – If the taxonomy were sometax, and taxonomy’s slug were someterm WordPress would look for taxonomy-sometax-someterm.php.
  2. taxonomy-{taxonomy}.php – If the taxonomy were sometax, WordPress would look for taxonomy-sometax.php
  3. taxonomy.php
  4. archive.php
  5. index.php

EDIT

If you’re already using taxonomy-{taxonomy}.php for something other than the index archive for {taxonomy}, perhaps you should re-consider your current use of this template file?