My starting point for any system design is that any user needs only a display with rich input, a network connection and an X server. That's an x terminal. In the case of voting you also need user verification, and that would need to be addressed. But the interactive display is only something that uses the network to eliminate distance as a factor, and is never something that implies/requires a local PC.
It's not a technical issue anyway - it's a political issue, a control issue. If I had time for it I'd try to deal with it, but I don't have the time. I would contribute my stuff in a heartbeat if somebody told me it would make a difference.
I invented the restaurant software paradigm and it's been picked up by the retail industry in general now, too, so I have no doubt that I could help put a voting software paradigm together pretty easily that could be trusted and that would be easy to use. Will the political powers, the people who obsess about control, allow it? Highly doubtful.