BenWhitanyone ever made one with pvc "rollers"?
Thays how my one was built - I could get endless PVC but astro turf was expensive. I have a slightly smaller diameter bit of pvc inside a larger diameter bit. The smaller diameter bit is pretty much drilled into timber rails on each side that join it all together. To be honest, without greasing the middle of the two regularly, they dont roll. However, it still works great for speed in conjunction with a smooth astro turf transistion - about 2m high at at about 30 degrees.
I havent needed to, but if you really need speed you can add some handles to the top of your drop in that allow you to push off as you drop in.