I'm a huge fan of SlideShow Pro Director!
I'm not sure there is anything out there off the shelf right now, like an add-on for example though, I hope I'm wrong.
With that said, have you considered using SSP Director along with it's DirectorPHP classes?
You could build your own add-on (recommended) or use PHP templates and build out your own gallery using their classes/methods etc and just use Director for the image handeling uploading/editing side of things.
If I remember right they are using Cake PHP for their API.
You can get more familiar with it here in their docs:
They have some examples here of how to use it:
And you can download DirectorPHP from your account center once you've logged in. Not positive if you need to purchase Director first or not, however, I'm pretty sure to connect to Diretor from DirectorPHP you will need a key from Director settings itself and add it to the DirectorPHP.php file like so:
# Fill in your API key here. It can be found on your Director preferences pane,
# under the "About your install" section.
public $api_key = 'your-api-key-goes-here';
# Path to your Director install
# This can also be found on your preferences pane, below the API key
public $path = 'your-api-path-key';
Note: the above code is from DirectorPHP 1.5 beta and may differ from the non-beta version.