You don't need much, there's virtual-MAAS now:

- http://jujucharms.com/~virtual-maasers/precise/virtual-maas

Not finished, here be dragons, etc. but it works.

I just spun up juju on AWS and was pretty impressed with how damn easy it was (the toughest part was looking up my AWS keys). Now I'm really excited to play around with it and see how it interacts with Chef.