Hey Dirtgrinder...one of my nephews has that same bike, and I have a question for you. Did you add the "other" two holes for the shock mount or is that the way it came? His only has one and I thought maybe if you added the other ones it would give you more tuning possibilities.

As far as the PVC pipe idea, I bet it will crack pretty quickly on the trails. It may hold up for a while, but after a few big hits it will probably be toast. But your not out much if it does so what the hay...give it a go and see what happens. Just be careful of fragments of plastic hitting your legs if it does explode.