A good choice 'Jean May' which is a strong growing sasanqua with dark glossy foliage and beautiful pink blooms in autumn. I have some espaliers that are informal -- no wires or other supports. Camellias are strong enough to be pruned to a flat shape without support. But if you want to train it in a formal design, wires are necessary. I would recommend keeping it a few inches away from the wall for aeration.