Great stuff. slippyfish (on these forums) deserves credit for the very first incarnation of the boston cross barriers - they were nice canvas, with wooden stakes, and had motivational phrases written on the canvas just so you wouldn't slack off as your mind started to drift to burritos.
I made a bigger version of those the next season with stronger sticks (v2 with dowels) but once the ground froze it was still hard to get them in deep enough. but they were very forgiving for newbies...so much so that the dowel would eventually snap if you really tripped up on them. Mark A really pimped them out with his v3 in that pdf - way pro, but less portable.
My latest version that I like a lot for its ultra-portability is yard sale sign posts (thin metal rods with two loops up top) and caution tape between two of the posts. Ultralight, adjustable in height/width, goes in the ground in a snap, and you can carry 6 or more in a backpack or messenger bag. Often implemented with the rule that if you knock em down/bend them/snap the tape you gotta stop to fix them.
We often would have a bunch so that we have every barrier configuration on the practice course - high speed, bottom of run-up, just before and after a hairpin, etc. But barriers, esp. high speed, seem to be an endangered species now and have a lower importance in the wed night worlds.