I think an electric bike with a top speed of 35-40 mph might be a good compromise. My build would ideally look something like this:
1K+ watt hour battery or batteries, frame integrated would be ideal, but highly unlikely with current tech
Throttle (unrestricted)
Top speed of up to 40 mph
At least 9 speed cassette
I'd even like to turn the bike into a two seater modding an exceptionally sturdy rear rack. Full sus would be awesome too. Of the commercially available builds, an FLX Blade might be pretty close. Perhaps a full suspension Frey with Bafang Ultra Max:
