Unfortunately Campagnolo don't make anything under 170mm. Truvativ's Roulers are the slimest that they make and I can't think of any realy slim ones off the top of my head. You could also consider Miche if you can find some. Some Campagnolo labeled gear comes from Miche and I think you can get 160mm cranks from Miche If you want to try even shorter.

Regards, Anthony