How large of a trellis are you thinking? Just 2-dimensional or did you want something with some depth to it?

I'm actually in the process of building a "trellis" made out of PVC much like the GardensUp structure. It's all put together and I'm almost finished spray-painting it hunter green so that it will look at least a LITTLE more natural.... Tomorrow I'll finish spray-painting and will string it up.

Total cost: under $50 including the cost of a PVC cutter and a can of spray paint AND 200' of 5/16" braided polypropolene rope (purchased at an army surplus store for WAY less than I could find anywhere else. I'm using mine for my watermelons and charantais melons and if all goes according to plan, I should have a 6' tall "cube" of green leaves and melons. *crossing fingers*

Will post pics of it as soon as it's up and in place.

Here is a link that might be useful: GardensUp website

Wow, that sounds awesome. I can't wait to see pics!