That's an interesting and complex plan. It will be somewhat effective, but not foolproof. I don't believe it's possible to "fool" rhizomes to prevent them from growing in one particular direction. I also have seen HPDE pond liner that was breached in multiple locations by rhizomes. I have rarely seen rhizomes go deeper than 12", though, so one thought I have to improve your design is to use real bamboo barrier instead of HPDE, and to install it at the backside of your raised bed so that the top side is leaning substantially back from the bamboo. That way, when the rhizomes start moving out and hit the barrier, they should slide up the barrier and pop out of the ground where you can see them and snip them off. In your Zone, clumpers may take a long time to size up and you would need quite a few for a 50' fence line, so runners are probably your best choice. If you go with runners, you'll want the hardiest ones you can get. One of the best ones for that purpose is Ph. nuda, which is hardy to about -20F. If you go to the link I have provided below, you can do a search on bamboo using various criteria to help you narrow down your list. One last thing: when growing a bamboo hedge, it is always wise to plant at least two species. You never know when bamboo might flower and die, and it's always best to have only part of your hedge fail. It might not happen in your lifetime...but you never know. You could also consider a combination of hardy runners and hardy clumpers, as some of the Fargesia species can also handle temps down to -20F. Good luck. Here is a link that might be useful: BambooWeb-Species

Bamboo gardens should have photos, or in the past, they've told me to drive to a particular neighborhood and so and so has a mature stand of such and such bamboo. If you didn't take the walk around, I'd highly recommend going back for a full tour, you may see what you are looking for. They've always been very helpful for us.

Look at the Fargesia species. These are very cold hardy bamboos (we have no idea where you are located!!), also quite shade tolerant and they are clumpers.........so will not try to take over the planet :-) I'd look for Fargesia rufa, aka Green Panda, as it is quite upright in habit and and grows to 8-10' tall.

I assume you are referring to bamboo shoots as being the edible part, in that case, all are. However, giant varieties (growing over 3") are pretty much what is harvested. I'm not an expert, but all the giants I've seen are running not clumping. You'll be able to harvest clumping shoots, but the pain to harvest a .5-1.5" shoot versus a 2-3" shoot, may make it not worthwhile. You might also cross-post to the Asian forums.