Since I've kinda dabbled in this too for the last 40+ years (music), and have a love of mixing technologies (music and computers... matter of fact, thats how I started in computers, via music and computers recording back 27-28 years ago), I think we need to better define what the OP wants and if it is viable.
There are some P&S cameras that do an ok job of recording voices via their mics, but to record from a PA system requires some kind of input (mic or midi).
I do not know of ANY camera that does this. Further more, if one was found, it was likely of extremely limited use as a device designed PRIMARILY as a photo taking device is NOT made to record sound.
Use a sound recodring device. My suggestion (as it was from someone else), is to use a laptop with the proper inputs. You can get most ANY kind of imputs available on the market, from multiple MIDI inputs to audio/video and even an extermal board for several mic (1/4" jack), inputs.
This would guarantee you both superior quality and lengths of available recording time as well as the ability to mixdown and also modify the sounds to your needs.
As a basic setup, one could start with something as simple as a portable laptop running something like Adobe Audition (great little app, I use it all the time). Use the mic inputs of your laptop and cable yourself into the PA system... and record away!