A workaround that you can try is tweaking your models.py as follows:
class Topping(models.Model):
.
.
.
class Meta:
verbose_name_plural = "2. Toppings"
class Pizza(models.Model):
.
.
.
class Meta:
verbose_name_plural = "1. Pizzas"
Not sure if it is against the django’s best practices but it works (tested with django trunk).
Good luck!
PS: sorry if this answer was posted too late but it can help others in future similar situations.