boundfield.patch

--- forms.py	2011-12-22 15:00:46.000000000 -0800
+++ new_forms.py	2012-01-11 16:00:17.771616110 -0800
@@ -69,6 +69,7 @@
     # class is different than Form. See the comments by the Form class for more
     # information. Any improvements to the form API should be made to *this*
     # class, not to the Form class.
+    _bound_field_class = BoundField
     def __init__(self, data=None, files=None, auto_id='id_%s', prefix=None,
                  initial=None, error_class=ErrorList, label_suffix=':',
                  empty_permitted=False):
@@ -96,7 +97,7 @@
 
     def __iter__(self):
         for name, field in self.fields.items():
-            yield BoundField(self, field, name)
+            yield self._bound_field_class(self, field, name)
 
     def __getitem__(self, name):
         "Returns a BoundField with the given name."
@@ -104,7 +105,7 @@
             field = self.fields[name]
         except KeyError:
             raise KeyError('Key %r not found in Form' % name)
-        return BoundField(self, field, name)
+        return self._bound_field_class(self, field, name)
 
     def _get_errors(self):
         "Returns an ErrorDict for the data provided for the form"
@@ -142,7 +143,7 @@
 
         for name, field in self.fields.items():
             html_class_attr = ''
-            bf = BoundField(self, field, name)
+            bf = self._bound_field_class(self, field, name)
             bf_errors = self.error_class([conditional_escape(error) for error in bf.errors]) # Escape and cache in local variable.
             if bf.is_hidden:
                 if bf_errors: