If you mean structures for overwintering bonsai, I believe I have seen some in International Bonsai - usually poly tunnels that are taken down in the spring. Michael Persiano had some info in Bonsai Today on wintering his bonsai under benches, if I remember correctly. White poly is draped over the benches. Clear poly supposedly heats the trees too much.
If you are looking instead for latice or shade structures, or just general supports or bonsai benches, You might take a look at "A step-by-step guide to growing and displaying BONSAI" by Colin Lewis and Neil Sutherland, Smithmark, 1993 There are some pictures of some light lattice structures in the chapter on Siting Bonsai - page 104.
If you can't locate this book, we expect to be carrying it as well as others at Treebay.com in the near future.
Additional hints on overwintering bonsai can be found here.