Before I bought my F/D I researched everything to death.In those searches I saw many pics of people disguising their F/D's very well.One was blocked from view with large panniers, a modified rack, and some mesh screen ( rider was worried about theft, thought the disguise made his bike less "shiny" to thieves), one was housed in the old style milk crate (I believe MB's were illegal in his parts), it was a neat build, and just "homemade" enough looking that unless he had a smoky/loud engine I don't see anyone spotting him while moving.
You could do a combo with your E-bike, say with a disguised bumblebee bolt-on and have one crazy efficient ride; before you get into town kill the petrol motor and hit the electric, get out of town and rev up, run out of one use the other,... you get the idea.