Even just a few layouts (2 knob, 3 knob, 4 knob 125B) where we could add text to text boxes for each knob and then a place to put a graphic in the open space on the top. An Adobe file (fill in the blank style would be great). Simply type in your text, choose a font, drag and drop a graphic and then email the file to you. That would be sweet. As for cost, If it is as easy as taking a file and sending to the engraver, then charge $10 on top of the cost of the enclosure.
So:
125B Powdercoated: $11 (cost for most expensive option at mammoth)
Engraving: $10
Shipping: $4
Call it $25 per box shipped. I could see that. Much more and it would be too costly for me.
-P