UPDATE: The "mystery" has been solved:
The check-writer is Ed Conard, who was a top official at Bain, the private-equity firm Romney helped create, and who has been a strong supporter of his over the years.____________________
From Isikoff at NBC:
A mystery company that pumped $1 million into a political committee backing Mitt Romney has been dissolved just months after it was formed, leaving few clues as to who was behind one of the biggest contributions yet of the 2012 presidential campaign.
The existence of the million-dollar donation — as gleaned from campaign and corporate records obtained by NBC News — provides a vivid example of how secret campaign cash is being funneled in ever more circuitous ways into the political system.
