I saw a post in here with home made cat trees.. If you have problems coming up with ideas. here you go.. some links to help you out.
http://www.ronhazelton.com/howto/cat_tree.htm
http://feline-furniture.tripod.com/
http://www.furr-angels.com/build_a_cat_tree.htm
http://www.showcatsonline.com/x/building_a_cat_tree.htm
http://www.ronhazelton.com/howto/cat_tree.htm
http://feline-furniture.tripod.com/
http://www.furr-angels.com/build_a_cat_tree.htm
http://www.showcatsonline.com/x/building_a_cat_tree.htm