Organizing Your Controllers into Sub-folders

[eluser]GeXus[/eluser]
I'm trying to organize into sub-folders, such as this:

/controllers/checkout/cart.php
(domain.com/checkout/cart)

/controllers/checkout/default.php)
(domain.com/checkout/)

I'm having trouble with the default controller. It just doesn't work, i get a 404.

I'd rather not setup routes for every default controller. Is there an alternative?

Thanks!