I would agree that 'Founders Edition' is not right as everyone who funds the project is essentially a founder as its crowd funded.
I do like the roman numerals idea as that is unique.
But something like; 'First Edition #1/500' would be clean, simple and not too intrusive on the design.
Someone mentioned about the unit number under the stand which again is another nice idea. So First Edition would go above or below the V logo and then hidden under the stand is the number