I attached a picture of my Kayak below; its not quite a popular model and is a little outdated, but I got it for a steal!
I circled the area where I'm trying to figure out what to build/buy to hold rods, tackle boxes, and other gear.... it has a center hatch that is waterproof, but that can't fit any rods or tackle boxes, just smaller stuff so I was thinking of going the external route; something I could take off if needed and could just strap down during launches/landings...
Any more ideas? I might give the acrylic a shot; I've worked with it before and would be a professsional looking box and I could easily mount some PVC pipe on the side for rod holders......