Another good idea, thanks! I'm going to carpet the front face of the bulkhead there where the fishing rods will enter the rod tubes. I was thinking about carpeting over the tubes, cutting some relief cuts over the holes, and then folding/gluing the extra 1" of carpet inside the tube.
If I can flare the ends of the PVC and make it look good, I think I'd paint the flared lips and spray a bit inside the tube (match the gunmetal grey) and then let the lip show instead of covering it with carpet.
I got the thick-walled PVC, so I'm not sure how it will turn out. I'll run some tests and report back how it turns out. Thanks again for the tip!