I recommend 'Hi Neighbor' which although it is not legitimately a 'climber', it is remarkably tall and agile enough to espalier. Height seems to reach 6' and could be more with pruning to encourage tall growth. It is a large cherry red bloom, with ruffled petals, a petal count of about 25-30, but alas, little or no scent. Moderately disease resistant (slight susceptibility to mildew) and tolerates climate extremes. It seems to be a challenge to find, however.
