Don't be afraid to consider the various clematis vines. Several of the most famous recent hybrids have been bred by a breeder who lives in Poland, where the winters are plenty cold.

You may or may not be able to find roses that will work for you on such a trellis, but the combination of Clematis + Rosa is a famous one, and it works.

Even if you can't find a climbing rose that will work in your climate (frankly, I don't know one way or the other whether you will find such a rose, and I recommend you check out roses like John Cabot & its kin for that purpose), I can't help but think that if you explore the possibility that you will indeed find a clematis vine that will work well for you, while still providing you with a worthy living, vining, blooming cover for your trellis.

I went to a garden symposium Monday that had Carol from Northland Rosarium as one of the speakers. It was a very interesting presentation and gave me a lot more confidence in my ability to grow roses. She's about the same distance from Spokane as I am and she grows all kinds of roses. I would guess we're in the same zone, or maybe half a zone difference (5 degrees).

I'm going to go out and visit her gardens this summer and see if there's anything more I should be doing for winter protection, but own-root roses have done well for her and I hope they'll do well for me :)

Any suggestions for changes in my trellis design? Does it need to be larger, further from the house, because I've seen plenty of pictures of roses growing on trellises attached to buildings. Thanks for the input.