Many people use freeze dried proteins (e.g., freeze dried chicken). The pieces break up pretty easily so if they have more options in the dog section of a pet store, you can easily make them into cat sized pieces (and the dog variety are less expensive than the cat sized).
ZiwiPeak has an air dried raw line of food that's like a jerky treat -- it may be more chewy than crunchy.
And you are correct -- Temptations are high in carbs.