The short answer is no, not really. The long answer is yes, with a lot of restrictions...
In essence the clientAPI allows you to easily hook into any element's events. For simplicity sake, lets say that you know the ID of the container you wish to add an event for (in this case assume cmdVisibility_1).
Assuming you wrote some server side code to hook into the page's onload event handler you could call your own function. (this is done with the DNNClientAPI.AddBodyOnloadEventHandler function).
function myonload()
{
var o = $('cmdVisibility_1'); //HARDCODED
dnn.dom.attachEvent(o, 'onclick', minmaxhandler);
}
function minmaxhandler()
{
alert(dnn.dom.event.srcElement.id);
}
Like I said, this is an oversimplification. First problem is that by default the expand/collapse uses animation for its logic, therefore your method will be called prior to the element being completely minimized. Animation can be turned off by specifying in your container's skin AnimationFrames=0. Note: the logic to do the animation and have a callback is supported by the ClientAPI, it is not supported by the DNN core at this time.
If I were in your shoes, I'd simply create a new visibility skin object and use it in your container's design. Sorry I don't have time to put one together for you to demonstrate this.