Chew toys that last for a while around here:
The Souper Gallileo Bone (I'm not sure if you tried this one or not): http://www.pet-shop.net/html/galileo.html
All things Orbee:
Raw bones are good, but I'm not personally comfortable letting the dogs chew on them excessively, they just don't know the meaning of moderation and dental surgery is EXPENSIVE. Also, they're too high value for them to chew on in 'company' and I don't want them on my (white) carpet, so they're not the sort of thing I can give them while they're just hanging around the house.
I do get the (non-splintering) smoked bones, which don't last terribly long, but they're not as high value and don't stain the carpet while still keeping those jaws busy: http://www.sitstay.com/store/edibles/bo ... tml#ED1015