I think we need more blue sky thinking here. Much of the power is consumed accelerating to rotation. So, a pair of steel main wheels with a longitudinally divided runway, positive on left, neg on right, possibly tricky in a crosswind, but a bit of pilot training should sort that. Then in case of unplanned flight diversion etc. a converted tanker with an enormous battery and a couple of heavy gauge dangling power leads for in flight recharging. Perhaps this could all be augmented by a massive elastic catapult.