Here's a link:
Just got to know - Insight Central: Honda Insight Forum
Have had independent verification of these numbers. Seems like he has his IMA removed, and the bypass he's using has a bug which disables lean burn, leaving some additional economy on the table. His secret seems to be running astronomical tire pressure (120+) and keeping speeds low enough (~40mph) that rolling resistance is his primary drag. He (I think) doesn't use a deep cycle battery and just uses the Insight's original DC-DC charging, and aero mods are minimal.
Probably worth a read.