My son swung both the Velo and the Machine by Rawlings this year. He ended up staying with the machine. The Rawlings bats are excellent and I would recommend any of the Three Rawlings 5150 models.
If they are good enough for D1 South Carolina and Kent state I would bet its a good choice for your son.
I saw more and more kids swing a 32" bat this year regardless of their physical size. Hope this helps you a little.
CNK athletic Equipment has the original 5150 in stock at a sale price right now.