If you want to order some custom-size dust covers, DigitalDeckCovers is a good resource. Very reasonable pricing and good service.
I'll second Digital Deck Covers as a good source for covers. I bought many from them to protect my entire system.
Their prices are reasonable, and the cover(s) will be to the exact sizes and specs you specify.
They can be gotten without their company logos on them, be sure to specify that should you order from them, and don't want logos.
You do the measuring, and one can account for bottom feet that the cover can be made a bit taller to fully cover the Amps.
I had many of my covers from them designed with an open flap on back. This permits the covers to be easily put on, and removed with less effort, and the flap allows clearance for cables, but still coverage and dust protection of all cables exiting the back of a component.