this may not help but the rv dealer just up the road from my shop has a big fiver that's all gold paint and sits on what looks like 20" or bigger "dub's", when i first saw it i wondered what was more over loaded, the low profile suv tires or the made in china ghetto wheels
i know i've seen aluminum trailer wheels it just if you ca find them that will fit your brake/axle combo, id make sure to coat all of the mating surfaces with antiseize if you have corrosion problems and do go to aluminum, adding aluminum wheels may create another problem that wouldn't be found out till the wheels are already welded to the hubs