I've had the same internal dialogue. I have a weekend place where there are lots of old logging roads, lots of hills and some long distances. Its fun on a regular bike but its just too much work and takes too long to get anywhere, if you are combining it with a hike for instance.
So if you scale up to an ebike that can handle all that, why not just get a motorbike? A motor cycle has to be safer than souping up a bicycle to go 60 km/h.
Anyway I am going to modify an old mtn bike to an ebike and see how that goes.