finding the telephone poles was not a easy task. if the poles are purchased new, they are very pricey, around $250 a piece, and we needed 30 plus poles!! OUCH!!!! however, we made a bunch of phone calls to electric companies, and private contractors to find them for much cheaper (bartered for a bunch of free playtime!) so, try giving that a shot, if the electric or phone companies cant sell them to you, they might be able to point you in the right direction.
here's a pic of one section of 4 x 4's that actually survived. (that section was 12' high and we get major bounce over problems) you can also see one of our telephone poles, and the height of netting we used there is 17'.