[asid61]

Looks pretty good. I'm wondering about that thrust bearing at the top. Is it only going throug one plate, or is there another one that we can't see? With the wide shoulder your bearing has it might be okay, but keep an eye on it, and maybe add mounting holes for an upper plate just in case something goes wrong.
As other have said, your lightening pattern is too aggressive.
I would also add another bolt to mount it on the siderail, as the lower-right bolt is only secure by the bottom of the 2x1 there, which is only secured by a gusset plate or bellypan, so it will move around.