A trike made from any other v-twin would be no wider than a standard bike. I have seen some around although I can't give you a link. I can understand. I suspect I won't have too many more years, but I can still bike better than mountain biking, canoeing, hiking, tennis, snow skiing, water skiing, and all the other things I used to do.
The new 2018 Yamaha Star Eluder I have has more torque than a GoldWing and I imagine would be a pretty good v-twin trike.