Here is another source for your blank control plate -
Tele Control Plate .080" thickness NO HOLE - screws not included - Philadelphia Luthier Tools & Supplies, LLC
I've used these plates and they are real nice quality
PLS's shipping charges are always pretty fair here in the States, and they do ship overseas.
Your idea to make one from aluminum is very doable - aluminum works pretty easily.
Stainless steel is another option, but it's a little tougher to work with
Out of stock for the chromed plate . I guess I'm diy-ing it.