widgets.py

from django.template import loader, Context
from django.utils.safestring import mark_safe

class MyWidget(forms.RadioSelect.renderer):
    def render(self):
        '''Outputs radios'''
        t = loader.get_template('my_widget.html')
        c = Context({"radios": self,
                     "name": self.name})
        return mark_safe(t.render(c))


# my_widget.html

<div id="div-{{name}}">
    {% for r in radios %}
        <span id="span-id-{{name}}-{{forloop.counter0}}"> {{ r }}</span>
    {% endfor %}
</div>