An update: I'm pretty sure that, at the moment, it's simply not possible to do an SS1000 on a standard electric bike - at least, not without swapping battery packs. Zero and Motorrad have set a world record for distance travelled, and they could only get to 1,317 km - about 300 km/180 miles short. That was done on an oval at a test track, so they were able to maintain a constant speed between charges. Zero had brought along extra charging equipment able to deliver 110 amps, and they used ice to keep the battery pack cool, so they could give the 14.4 kWH pack a full charge in an hour. Pretty much ideal conditions.
Unless there is some breakthrough in either battery or charging technology, it's difficult to see how the situation will change, either. Improvements in battery capacity will allow the distance between charges to be extended - but will then need more time to recharge. OTOH, if you're about to order a Zero, they are offering £1,317 of accessories free, to mark the achievement.
You can read the Motorrad article
here.
Regards,
Martin