There have been several threads on different specialty ponds created for specific purposes. Examples are for sediment control or for forage fish production. They generally don't fit regular pond management and may even have very different construction.
I have tried to look these up several times and it is a hassle to find them all. Catmando, FireIsHot and myself are three that come to mind. There is another one that had a complex set of ponds and even diversion terrace to control water flow into the pond that I have read tried to find again with no luck. Having some links to these ponds in an archive I think would be beneficial to anyone contemplating creating a specialty pond.
Edit 2-26-15 - I ended up looking up many of these ponds mentioned above and added those links to the end of my snrub's sediment pond thread. Links start at the bottom of the first page and mostly on the second page
of the thread. Will add any additional links to threads I find to this thread instead.
Below is my unofficial list of links to additional specialty ponds.