configuring drupal to use unicode characters
After further investigation: "" and other characters beyond the Basic Multilingual Plane need to be stored in a database set up with the "utf8mb4" charset.  The general configuration steps are very nicely described here:

http://mathiasbynens.be/notes/mysql-utf8mb4

In addition to updating MySQL to 5.5.28, and doing the basic tweaks outlined in that link, in order to get this working with Drupal, I needed to take some further steps:


Replace SET NAMES utf8 with SET NAMES utf8mb4 in includes/database/mysql/database.inc
Modify settings.php to include the following

$databases = array (
  'default' =&gt; 
  array (
    'default' =&gt; 
    array (
      'database' =&gt; 'DB',
      'username' =&gt; 'UN',
      'password' =&gt; 'PW',
      'collation' =&gt; 'utf8mb4_general_ci',
      'host' =&gt; 'localhost',
      'port' =&gt; '',
      'driver' =&gt; 'mysql',
      'prefix' =&gt; '',
      'pdo' =&gt; array(
                     PDO::MYSQL_ATTR_INIT_COMMAND =&gt; "SET NAMES utf8mb4",
                     )
    ),
  ),
);

And modify the table and column (per the page linked to above) where the fancy UTF8 characters are to be stored:

ALTER TABLE tn CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
ALTER TABLE tn CHANGE cn cn longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;