OK , I had a little more of an OO approach for this:

    self._migration_context = MigrationContext.configure(
        connection=connection,
        url=url,
        dialect_name=dialect_name,
        opts=opts,
        environment_context=self
    )

	--- a/alembic/migration.py
	+++ b/alembic/migration.py
	@@ -110,6 +110,12 @@ class MigrationContext(object):
	                         "transactional" if self.impl.transactional_ddl
	                         else "non-transactional")
	 
	+    @property
	+    def config(self):
	+        """Return the :class:`.Config` used by the current environment, if any."""
	+        return self.environment_context.config
	+
	+
	     @classmethod
	     def configure(cls,
	                 connection=None,

etc.   can we do it like that?  thanks.