I was looking through some aquarium forums and saw some crayfish, so I went looking if there's any species that can live in colder water (ie fish pond) as well, and I came across this interesting little species:
Marble crayfish (Procambarus sp.)
They are very hardy, and can live in water with temperatures ranging from 5-35 degrees Celsius. They grow only to about 8-12cm. They're all female; they reproduce parthenogenetically, so they're basically cloning themselves, and they seem to do it quite a lot. Also means that a single marble crayfish can populate large bodies of water in no-time, so they're illegal in the UK for instance.
Anyways, they breed very easily (you could literally breed them in buckets), eat just about everything, aren't very hostile to eachother and they can live in a wide temperature and water quality range.
I've heard they taste quite okay if you BBQ them for instance. They could also be used as live feed for other aquatic organisms.
Here's some more information:
http://iz.carnegiemnh.org/crayfish/cfre ... rph261.pdf
http://iz.carnegiemnh.org/crayfish/cfre ... EZ303A.pdf
http://de.wikipedia.org/wiki/Marmorkrebs (German)
They're legal to keep in the Netherlands (marmerkreeft) and I think also Germany (Marmorkrebs), where you can easily get them, but I'm not sure about other parts of the world.
They seem quite suited to AP to me.