Dick,
I am sure that the paper is as damming as you think. Their focus in that paper was on commercially viable aircraft for transport and that I do think that is a long way off. The electric aircraft that can do this now is a practical for taking the family to Bali as the Victor Vimy.
Look at figure 16 in the paper. This shows that if the battery energy density is 250whr/kg, the mbattery/mtotal is 0.6 and the L/d is 20 you can get a range of about 750km. With careful consideration of logistics this might just be enough.
These numbers are achievable with current 2016 technology but with a significant amount of development work.
If you can get the L/d to 40, The energy density up to 300whr/kg and the mbattery/mtotal to 0.7 and by that graph it romps out to 2500km range.
Imagine a single seat version of the
Stemme S10 with a 600kg battery, 70kg pilot and about 250kg of structure.