Do most camcorders (sub $1000) have some way of limiting extremely loud audio during recording? For example, will most camcorders do a decent job of picking up sound at a live concert. I know not to expect great quality, but I was wondering if the sound would be blown out and distorted. Any recommendations on a good line of camcorders to look at would be appreciated. Thanks in advance.

Of course, every microphone has its upper limit before the mic itself can't handle it, but I believe that just about any consumer / prosumer miniDV camcorder will have Automatic Gain Control (AGC). A few of the prosumer camcorders allow you to switch to manual settings -- you pay more to get manual control of your audio! I'm pretty sure AGC is a "given."

The camcorder with on-board microphone will not pick up what anyone would call 'professional' quality sound. It just takes more and better placed gear than that.

That said, you will probably get a reasonable result with an on-board microphone unless you are standing next to the loudspeaker stack. Reasonable means that you will hear the music with the crowd sounds mixed right in.