Hi Annie,
I've been wanting to grow morning glories for the last several years. Have lots of different seeds to try. As is often the case though, what I want to do is much more than the actual time I have to do things so this idea is one of the ones that has been sitting on the back burner. I've been wondering the same thing about trellis/arches, etc... so will be interested to hear what you come up with. When I'm on Pinterest, I keep an eye out for possibilities. The setting of this one is a little too modern for my garden style, but I think I can easily adapt the trellis idea shown in the photo. I was thinking of making a connected series of these as a freestanding element somewhere in the yard that actually receives some sun - maybe three to five sections. Looks like simple construction - something for the posts and then just wire between for the vines to climb on. I'll probably use pressure treated 4 x 4s with the white PVC 4 x 4 post covering that is available at the big box stores, but landscape timbers (are they different from 4x4s?) would work as another possibility.