Yesterday while waiting at the Arch for my DoE group to arrive, this rode past.
I've never seen one before. A quick search revealed that they're marketed more as a training / fitness aid rather than a bicycle. However, the one in the pic had a 11 spd Alfine and I saw the fella later in the day on the mountain road to Mach' so if he was doing a loop it'd be a 70 - 80 mile day.
He'll have been on the Mille Cymru 1000km audax running this weekend.
I heard three elliptigos started, I think I read at least one had failed to make the time cutoffs at checkpoints. One or two elliptigos successfully finished the 1400km London - Edinburgh - London audax last year.
I was signed up (bike not elliptigo) but life got in the way :(