the guy had cut the top of the five gallon bucket and used it like the nylon wheel gebe sends with its kits, it had the same sort of gap pattern imposed on body of the 5 gallon pale, so he was able to attach the top inch or so to his 20inch wheel and hang the engine of the rear. the trike was a tadpole and worked out really well.
i have ridden both styles tadpole and delta, the tadpole is for sure the more stable on the road lower center of gravity easier to corner etc but i love the delta as well, although not as stable its a lot more fun to cruise on, very relaxed sitting position and you higher up from the road.
However the tadpole trike will be the easier to motorize and you will have more options because you only have the one rear wheel, you can motorize the deltas its just harder because of the rear wheel config, chain drive kits available from staton, would a gebe style work, not sure, powering just one wheel could be sort of tricky, good for tight circles!!!!!
anyhow just my 2 cents hope it helps, my wifes ez3ax delta trike is electrified and alot of fun too ride, and lying in a box somewhere i have a kit too turn any bike into a delta trike, i see a crazy build in the future.