Those are pretty much your only options as far as aluminium goes.

You can buy some delrin tubes but they are fairly pricy. The delrin fronts are nice, just wasnt a fan so I dropped using them on my one truck. Love his delrin rear tubes though, helps keep everything straight and fool proof.

http://www.hessemachine.com/uploads/..._2-24-2013.pdf

I race all my trucks so how much bashing they can take is unknown to me. I have seen them take a licking and shrug it off though.

https://www.youtube.com/watch?v=ws83V7JTSj4 (25 seconds)