Making large numeric displays

The following may-or-may-not suit the esthetics you want to achieve, but it certainly would have a retro/low-tech aspect to it: Revert to the 10-layer technique used in the early-mid-sixties. Each digit is made up from 10 layers of clear plastic, where each layer has dimple/dots/pixels forming 1 of the 10 numerals. Light is injected into a layer from the side and refracts out when it hits the dimples. The orginals used incandescent lamps of course, and can be found in early Canon calculators, General Radio digital test equipment, and occasional other bits of equipment. See http://www.vintagecalculators.com/html/canon_canola_130s.html (great pictures) or http://www.oldcalculatormuseum.com/canon161.html (I believe the units from General Radio were actually larger, perhaps 1.5-2 inches digit height.) (Trivia: These displays can be seen on the countdown timer on the atomic bomb in James Bond - Goldfinger.) It does have the disadvantage (as with Nixies) of interference from all the layers, but you also get that cool 3-D effect as the numerals change. Obviously this technique could be updated with LEDs and scaled up in size. A little experimenting might show whether it would be worthwhile in terms of LED count vs brightness, etc. It would probably be even easier to make in larger form as there would be more space for positioning and isolating LEDs at the edges, and interference effects might be reduced by being able to make a finer dimple pattern. As well it might be possible to make each layer just a rectangle and avoid any bending or tabs. Make up a drilling template for each numeral and just drill partially into the layer to form the dimples, the end of a drill bit leaves a surface perfect for refracting/diffusing the light out. Or farm it out to a plastic-machining shop with a computer-controlled-machine, they could zip off multiples in no time.