Re: Can I buy these?
If it were me, I'd either make something, or if I was looking for fast and cheap, I'd just look in the local hardware stores for aluminum shelf brackets.... you could even get some powder coated if you want.
Almost anything you bought would be stronger than those were, looks like.
They're not strongly structural either... you could replace them with anything that would do the same job, like wood diagonal braces or similar.
Erik