Check out 80/20 extrusion to make your DIY hanger (www.8020.net). It's very easy to work with and I've even seen this stuff on Amazon. Oh and I'd suggest purchasing the black anodized color.

Make a rectangle big enough to pick up all your units and drill the extrusion to pick up the attachment points on the Radions. Tip: make a poster board template to locate the 4 pick up points on the Radions. You'll need to pick up a generic hanging kit along with some T-Slot bolts. You could probably make the entire hanger for around 100 and I personally think it would look very clean. Let me know if you have any questions.