ISO Color Laser Engraver or Direct Print to Speaker

Hey Cube! I am on the hunt for a vendor to direct print or color laser engrave onto a metal plate on speaker for a swag giveaway for a concert. The client does NOT want a vinyl or sticker (yes yes thats the easiest way...) but I am having a tough time finding someone to print directly onto these due to their shape and the fact it needs to be a gradient color logo on the speaker. A fun combo ;) I have tried the usual suspects for film printing and I am working with Deboer to come up with a potential solve, but I just wanted to send out a wide search to see if anyone has a vendor that they have done this before with! Here is link to the speaker we are looking to add branding to. http://www.gemline.com/us/brookstone-bluetooth-drum-speaker-p70225.html#item=70225 Thanks a million!