Someone on a German forum a few month back claimed to have riden a prototype of a bike with a new shimano motor and 48v system, they got shot down but where pretty adamant that there was another motor apart form the EP8 out there:
"Yesterday I was allowed to briefly test a prototype of a German small manufacturer with the new Shimano in the parking lot. It is very small, identical to the SL1 from Specialized, but should continue to deliver 500 watts. Probably with 48 volts, for more efficiency. That is why it probably works as a light ebike unit (target weight for the bike yesterday with a 375WH battery should be 18 kilos). Appeared to me (under light load) very quiet - similar to Fazua".