North Creek Farm is near the coast and is in zone 5a or 5b. Any of her rugosas would do well if that's what you want, but some of the OGRs offered could be iffy in zone 4. Definitely William Baffin would be a hardy climber. I agree with New Dawn, in a bad winter you could lose a lot of cane or even have the rose die. The rest of the Canadian Explorers are very hardy if fragrance is not important to you.

Probably not true climbers, but maybe shrubs with flexible canes. The lamppost will need pegs or something to tie to. If you plan to spray fungicide regularly, there is a wide selection. If not, there are not many roses that will stay neat-looking. So, 1. Will you be spraying? 2. How wide a plant are you envisioning? If you are thinking narrow and neat, a vine might be better than a rose. 3. What is the color range? 4. Do you have a strong preference for a particular flower type? Bear in mind, many bush roses will grow to 6-7' with no support. You could look at Renae, a small flexible climber that is disease resistant and nearly thornless.

I just saw this post and wanted to say that I think you will be pleased with Illusion. The blooms are very pretty - 4 inches in diameter. They grow in clusters so the "show" is quite nice. Mine has no fragrance but is more disease resistant than other roses. It does need to be sprayed, though, in our zone 5. You could probably get away with not spraying it as often. This rose is VERY winter hearty. I hardly had to cut off anything this year! The repeat is not great so far but the first flush lasts quite awhile. It's a sturdy grower but not overly vigorous. It would grow nicely on an arbor.

The only one I can think of that would definitely be tall enough AND have the repeat/recurrent bloom you're after is the lovely old Noisette, Mme Alfred Carriere. She'd be fine with morning sun only, and is an extremely beautiful rose, with the most delicate, though informal, palest blush to white, prolific blooms. Normally very healthy and trouble-free, although she does apparently mildew in certain areas/microclimates - you might want to check locally. You might also want to plant something around the base to beautify her bare lower canes. Fragrance is strong, and as delicious as her lovely flowers. Comtesse :¬)