We will soon be offering a foot delete kit for those using external footers. They are entering production shortly and are available now for purchase. We love our products and want them to look their best in any installation or configuration. 
While we are very happy with our current Viton feet, this was requested for a custom Sentinel DAC Installation and I thought I would bring it to the Cascade DAC as well.
-Dan
MSB must be prescient, just what I needed.
I just ordered it… 
Dan
We certainly try! 
Dan,
Just an FYI as to the delay. We got early feedback that it would be helpful to have a threaded hole in the center for attaching aftermarket feet. We are currently re-working the design to include an M6x1 threaded hole. Some of the aftermarket brands said their feet perform better if rigidly mounted to the chassis. Cheers!
Again, you are prescient. I was about to look at isolators in my new rack design!
Dan
Dan
Well now you will know what stud to order them with