Cannot create bootable El Capitan USB media using "createinstallmedia" or Diskmaker X

Hello all,

So far (knock on wood) El Capitan has been fantastic on my 2011 MBP 13" i7, and has actually improved everything, especially performance. Some minor glitches here and there but I was expecting it.

However, one BIG thing I've come across is this... Whenever I go to try and create a bootable USB installer using either the embedded "createinstallmedia" command found within the El Capitan package, or using Diskmaker X v5.0, both methods successfully create the USB installer, but neither method generates a USB device that I can select as a Source Disk in System Preferences, nor will it recognize as a bootable device when I hold down the Option key starting my Mac.

I've tried using 4 different, reputable brands of USB sticks, ranging in size from 8GB USB 2.0's to 32GB USB 3.0's, no effect, and I've tried them on 4 different models of Mac's, all on the certified El Capitan compatibility list. Each machine won't recognize it as a bootable source.

My first attempts at making the USB's were actually while the Mac was still on Yosemite, so I don't think this is a El Capitan bug. It almost seems like the image created from the package doesn't contain the boot components.

Has anyone else here experienced this issue, or possibly found a way to fix this and make it work? I have three Mac's with blank drives I'd like to put onto El Capitan, but can't until I manage to create a bootable USB.

Thanks in advance!