I made a set from aluminum golf cart wheels that work just fine. Been using them all season now. I have a brand set set of cat trax as well and I haven't felt the desire to put them on the trailer instead.

They are ~10lbs heavier than the trax, but that's most because I haven't bought smooth tires for them yet.

I have one more pair of wheels that I made as well at the same time. If I did it again, I might sand cast the parts instead.