As long predicted, Super Tuesday voting on electronic ballots is highly circumspect. But we don't want to bring back the hanging chad, either!
How hard would it be , for electronic voting systems to simply assign every single vote a unique ID, print out that ID and the actual vote results on a slip of paper in barcode form for the voter, and store the vote by ID number only in a public database for 5 years, accessible by a simple web-based form?
Only the voter would know how they voted, because they have the barcode ID. They can lookup their vote on the public website to verify it. The hardcopy has the actual vote printed, so its a simple matter to verify the data.
For any audit or recount, everyone who has their paper slip sends it in or drops it off. From that subset of verifiable votes, the fraction of invalid ones is estimated. If the invalid vote count rises above a threshold of 2% then the results are deemed corrupted and the election certification is canceled (what happens next is based on local law). As long as the invalid ratio is below that threshold, the unverified votes (with no corroborating slip of paper) can be considered valid.
Note that the above proposal could be mandated by law, putting the burden of compliance on the manufacturer where it belongs.