I can't understand why no one has yet come up with the idea of integrating a touch-screen voting machine with a ticket printer from those Lotto machines.
The voter somehow identifies him/herself (for example my registration card has a serial number I would type in) and votes on the touch screen - you give them as many chances to back up and undo as there are potential votes - maybe with a "record your vote" button at the bottom, and a "ARE YOU SURE? THIS CANNOT BE CHANGED AFTER YOU PUSH THIS BUTTON" or anything you want it to say.
Then, the machine prints out the choices on a paper ballot, a la lotto ticket printers. This is also machine-readable, but there's paper if the counting machine fails.
In fact, you could even use ballots like lotto playslips, but that kinda obviates the use of machines in the first place. ;-)
I've written a letter to the Orange County Register, the closest to a Libertarian paper California has, and said I'm available for the design job if anybody wants to capitalize me. :-)
If they print it, you guys will be the first to know, after the paper's readership. ;-)
Cheers! Rich