Turbo Chassis mainly builds drag racing parts. That said, they do customer swingarm builds. I have two myself.
If you want MX style/capable parts, then Fireball hands down builds the best products for the money.
They also build many other vendors parts, who then slap their own sticker on them.
Give Roger at Fireball a call and talk to him. He's super easy to talk to and can get you going in the right direction.
559-324-9533
Tell him you got the info from BansheeHQ.