There is an excellent bicycle "Bullit" and you can add a BionX or any 48V kit.
This specific frame can take roughly 600lbs but the limitation is always with the wheels/spokes. Heavy duty double wall rim + 36/ 12 gauge spokes both front and rear, it should handle 450 lbs easily.
I really like the Yuba bikes but I don't think they offer a tricycle. Court reviewed a tricycle from Pedego but I didn't see how much it could carry. It doesn't look like much. Check out this truck trike I mean wow you could really move something with this! I like the Johnny Loco Cargo trike but it weight limit is just under 400lbs.