I don't know of a camera but that would be nice. I've heard of factory systems on other vehicles that will auto-sense when you are getting close to an object curb/car and it will auto switch the display to a front facing camera. That would be perfect because you know you could trust it.
On my 2010, I used a "Curb Alert" http://www.curb-alert.com/
This was pretty good but seemed to work about 90% of the time which could give you a false sense of security. It wouldn't work on angled parking curbs for obvious reason and sometimes randomly just wouldn't alert.
I googled a bit and figured out what "Lock Pick" is...they don't show support for 15+ Mustangs but I sent them an email. If they email me back with a solution I will post the info.
Looks like the "Curb Alert" has a pro option that comes with a camera. Now the questions is how do I hook it up to the existing screen in our cars or stream to my cell phone...the search continues.
On my 2015 F-250 with my ford touch I was able to just splice in and use a toggle switch and relay and add a second in bed camera. Has to be an NTSC camera but u can buy and aftermarket "reverse camera" I'll try and find my wore diagram I used it was very simple
I know its been awhile for this thread, but a company called Brandmotion makes a dual camera adapter (kit 9002-2781) that would allow you to add another camera such as one for the front. Its a bit pricey @ ~$300 just for the adapter so I haven't pulled the trigger yet, but thinking about it.