I’ve seen an older Barrett aluminum gooseneck with dual tandems.I have a steel gooseneck dual tandem,I know the 3 axles are way more popular but I like the dual tandems.
I would imagine any of the trailer manufacturers will build a dual tandem aluminum if a man was patient and willing to spend the money, last time I ordered a trailer was in 21 and it took about 10 months to get it built,not a stock trailer but a Wilson flat bed.
My only experience is with Wilson and I think  they would build it however you want it.