Me, me! *waves hand frantically* I have a cattle panel trellis and I love it!

Note that mine is a trellis rather than an arbor. I have no experience with cattle panel arbors except that I may someday use one as a gateway.

My panels are an extra-heavy weight -- that type just happened to be on sale; I'm sure the regular weight would be fine if well-supported. Unlike concrete reinforcement wire (CRW), the panels will not rust, so you don't have to worry about them weakening with time (though even CRW lasts ten or fifteen years or more, IIRC).

My panels are held up by T-posts (one at each end or where the panels join). The panels are attached to the posts with what looks like aluminum wire about 1/8" thick, near the top and bottom of the panel. Where the panels join, they overlap by a few inches or one square of wire. [As you may guess, I didn't build them myself.]

Since the panels are less than 5' tall, I had them raised about 15" above the ground. That makes the top close to 6' off the ground, which is about as high as I can reach. When the tomatoes get to the top wire, I train them to go sideways along the top of the panel (at least until things get too crowded).

In the spring, I cope with that dreadful in-between stage -- where the vines aren't tall enough to reach the bottom of the panel, yet need some help -- by a judicious use of jute twine.

I weave the vines through the holes, from one side of the panel to the other. But I also use the circular plastic clips to attach the vines to the panel, both to train the vine where I want it to go, and also to guarantee the vine won't collapse under the weight of the fruit. I don't know how much that's necessary, but a neighbor had her tomatoes collapse this summer (tied to stakes with strips of old cotton knit clothes).

The first time I used the trellis, I planted 2' apart, on alternating sides of the trellis. I'm sure that wasn't why everything died of Late Blight -- but they were too close. This summer, I planted the tomatoes 4' apart; not room for as many plants, but it works very well considering I pretty much don't prune.

In any case, this is way easier to deal with than any alternative I've tried. I have a few of the old (probably 25-30 years old), heavy, wide wire cages, about 3' tall. I planted a Rutgers in one. The tomatoes are so large and grow so tightly together that in order to harvest the fruit, I've almost had to dissect them to get them past the stems and the wires. No problems like that with the tomatoes on the trellis!

Besides tomatoes, I grow cucumbers and small gourds on the trellis.

Thanks for all the great info! I have raised beds set 3' apart with rock path between them, so my plan was to build an arch that starts in one bed and ends in the other with the path down the middle. I was only going to build one for green beans because they continually outgrow my 5' trellis every year. But now I'm thinking multiple arches to support all my tomatoes.

I love your idea about weaving the vines in and out of the squares. I'm also wondering if, while the tomatoes are small enough, I can train them to hang on the inside of the arch so they're protected from the sun when we get those 100 degree days in September.

I appreciate knowing this stuff will be tough enough to support tomatoes. I haven't actually gone to a fencing store to see it for myself. Just pictures at this point.