I have some number of trellises scattered over the yard that I've made. I'll put together an article/idea over the next couple of weeks complete with photos and maybe even a to-scale plan or two.
I'm really a novice welder, but trellises are a good thing for me to start with because they don't have to be perfect - nor is anything particularly critical about them failing, if they do (versus welding a trailer or something on the car). Nice things to learn on.