My dog Brandy is a "tough chewer." She loves to tear apart toys with squeakers in them, throwing the stuffing all around the room. Aside from clicker training, it's her favorite pasttime! But since the average soft toy with a squeaker lasts less then 5 minutes with her, it's an expensive hobby.
I've found some "soft" squeak toys that can stand up to Brandy's chewing, at least for a little while. The "whirrly" toy has held up to Brandy's part-time chewing for almost a year now, although admittedly it's not her favorite toy. (She'll always choose a more desctructible toy if she has a choice!)
While these toys are tough, they're not indestructible, so supervise your dog's interactions with these toys when he plays with them. The "whirrly," the "tugtoy," and the "flyer" are likely to stand up to the most abuse; the animal-themed toys may lose their limbs to really tough chewers.