Last of the MM3 dinosaurs is the 2 RHD, small-sized swindlespitter (which by the way is a very overlooked druid companion that is definitely interesting at low levels).
The chassis is pretty okay. 2 RHD aren't that bad, 20 dexterity sure is nice, the mental stats are surprisingly high, and the two bonus feats (Mobility and Weapon Finesse) don't hurt either. The special qualities are Uncanny Dodge, Darkvision, and Scent, which all have their uses. The dinosaur also gets small racial bonuses to Spot and Listen, as well as Hide and Move Silently while in a forest.
The swindlespitter has one natural weapon, a beak (which isn't the same as a bite and doesn't benefit from the same support). Furthermore, swindlespitters have the ability to breathe a sizeable cone of poison mist once per 1d4 rounds, which causes blindness for several minutes (the secondary effect being minor constitution damage).
Given that a fair argument can be made for swindlespitters having functional hands, I'll assign +0 LA. Progressing this creature may be a bit tricky, but it's got a fairly good early-game ability and leaves a lot of room for class levels: something functional can be made out of it.