Tsk... there WERE small ones! Get yourself a Sinosauropteryx

"Sinosauropteryx was a small bipedal theropod, noted for its short arms, large first finger (thumb), and long tail. It is among the smallest known non-avian theropods, with the holotype specimen measuring only 68 cm (27 in) in length, including the tail.[2] This individual was relatively young.[3] The longest known specimen reaches up to 1.07 m (3.5 ft) in length, with an estimated weight of 0.55 kg (1.2 lb)."