I did the PVC tube also with an expanding plug on the open end (glued a cap on the far end). It doesnt hold the reels but I am more worried about banging around getting damaged than being ready to cast in seconds. I actually find it takes longer to get them out of the socks I use than to take them out of the tube (I didn't want them banging around inside the tube unprotected).
I like the idea of mounting a small/thin metal box lined with rubber with a larger area at the back for my reel so I wouldnt have to break it down to travel. My thought was a "box" just over 9' long with a door on the back end. Get done fishing, slide it into the "box" with real still attached and line still run through the eyes.
Many times when out in the woods I will go from stream to stream and it does become more of a pain to take it out of the tube and set it up for a stream I might only try a few casts on. I have just broken it down leaving the reel and line in place but did have one get broken that way when we hit a bump that was larger than expected and something shifted in the back of the truck. Before this i want canoe for solo fishing but after some time. I thought this is batter then
solo canoe When travelling a distance the PVC works well.