How about Texas Toothpicks by Merrick? Both mine love it but it only lasts few min with Magnus.. But then, he's 16 lbs so... Zoey seems to take much longer though. If I were to just give it to her, TT is what I'd get rather than bully sticks/raw hides.
You said you use Kong.. How about a treat ball? I have the Omega Paw Tricky Treat Ball. Both M/Z loves it. Even the small seems big but the "dimples" on the ball makes it easier for small mouths to grab. Below is the ball I'm talking about.
http://www.amazon.com/dp/B0002DK26C/...w+tricky+treat