There is a ton of really good metal that looks like it is being thrown out on the uvic campus. There is everything from like 20 cm diameter to super skinny. Some of them look around 20 feet long and already have threaded inserts welded on so you could easily screw legs onto them and have a legit easy shotgun rail.
I already took some to make coping for a mini ramp. I would take more but my truck is in AB and I wont have a yard next year.