Planting too close to the wall will mean the plants struggle for water and nutrients. It woul dbe best all round if you can dig out a border at least 3' deep and plant other stuff between the climbers to hide the base of the wall but the first job would be to get the holes drilled to take the vine eyes and then stretch and tension strong wires between them.
Then you would either prepare planting holes or dig the border and start planting along it. I reckon you have room for a big ramblming rose planted in teh middle of the big wall. Kiftsgate (creamy white) or Paul's Himalayan Musk (lilac) will cover 9 metres heigh and 6 to 9 metres wide depending on training and both will provide perfume while in flower and then hips. I woul dthen a plant the clamtis montana half way between the middle and one end and the honeysuckle half way between te middle and the other end. You could also train smaller ramblers along the lower wall - see her for scented options, colours and sizes - http://www.oldroses.co.uk/cart/index.php?main_page=index&cPath=22
Plant them at least 2' 6" out from the wall and bury any graft union on teh roses at least 2 inches deep, sloping the plant back towards the wall. As the shoots grow, tie them in as horizontally as possible to encourage flowering shoots. make sure ties are loose enough for the stems to move in the wind and not get rubbed and damaged against the wires.
I would then advise perennial plants and bulbs to fill the remaining gaps and extend the season of interest - snowdrops, narcissus and hellebores for winter and spring interest followed by hardy geraniums, aquilegias, phlox, heleniums, achillieas and any manner of perennial to take you through from spring to autumn and hide the base of the wall.
After a couple of seasons you'll need to take out a third of the main rose stems and any dead stems every spring to maintain growth and vigour. The clematis and honeysuckle will only need pruning to keep within bounds.