On September 3rd, 2016 I ran the Double Presidential Traverse in 13:04:10, starting and finishing at Crawford Notch. My northbound split was 6:14, descending off Mount Madison to Appalachia on the Watson Path and returning the same way. I'd been hoping to slip in under 13 hours but didn't push hard enough on the final descent down the Crawford Path. Still, it was nice to do the whole thing without a using a headlamp at this time of year.
I’d say it was unsupported; I carried all my own food and took water from public sources at the huts and observatory.
Doing the double is probably easier than having to make awkward small talk with strangers when you hitchhike back after a single traverse.