Aluminum plate that thick would cost around $100 for us to purchase. Then we'd have to machine it (which would take 3-4 times as long as machining plastic), tacking on labor costs. Then, we'd have to charge extra to make a profit. Then, it would weigh much, MUCH more, increasing shipping charges. If we were to do an aluminum mounting plate, we'd probably have to charge somewhere in the neighborhood of $200-$250 just for the plate itself. Then add on the shipping costs... Yeah, it can get expensive quickly. UHMW is very strong, lightweight, and inexpensive. Machining time is also greatly decreased, being plastic. UHMW is the way to go. That said, we understand that not everyone will like it. Thanks for the feedback! Side to side motion might be an option. We'll see about that. Perhaps we can offer two different versions.