I found this handheld gimbal holder on Amazon.  It attaches to the P3P by removing the propellors and attaching the frame with supplied nuts.  My question is this - it shows a pad holder attached to the front of it.  Is there a USB connection from the drone to the pad or would it have to be a very long USB cable from the romote to the pad??

Can you give us a link so we can take a look at it?

Most of these devices were designed in the P2 timeframe where wireless was used. When used with the P3, you must use the Remote. Here's one variety:

ELEPHANTOM

I would design one that attaches to the landing legs, so you could hold it from the bottom, so u could leave the props on.
Would be really useful.