Bike hauler Teardrop?

Hi, I'm a noob here. I've been checking this site out for ideas and finally got registered.
So here's what I'm hoping to build. I'd like to use the teardrop design incorporated into a toy hauler to haul a motorcycle in. My biggest concern is structural integrity in the rear end since I won't be using the traditional galley, that space will need to be open to get the bike in and out. I'm hoping I can brace the rear with metal supports as shown in the drawings (I need to learn how to use Sketchup). The bike will probably be my DR650 (380lbs) but I'm sizing it to also fit my Tiger 800 (500lbs.) if I decide I'd rather take that bike. Only one bike will go at a time given the space restrictions. I started out thinking a 5x5x10 should be big enough but might stretch it out to as big as 6'W x 5'6"H x 10'L. I'll be towing with a Sienna minivan so weight and aerodynamics are important. Hoping I can start with a landscape trailer if I decide to go with the drop down ramp design and incorporate the built in ramp.
Here's the ideas I'm starting with. I'd really appreciate any feedback I can get. My carpentry skills are decent enough but I have no welding skills so will have to hire that out if needed.
So here's what I'm hoping to build. I'd like to use the teardrop design incorporated into a toy hauler to haul a motorcycle in. My biggest concern is structural integrity in the rear end since I won't be using the traditional galley, that space will need to be open to get the bike in and out. I'm hoping I can brace the rear with metal supports as shown in the drawings (I need to learn how to use Sketchup). The bike will probably be my DR650 (380lbs) but I'm sizing it to also fit my Tiger 800 (500lbs.) if I decide I'd rather take that bike. Only one bike will go at a time given the space restrictions. I started out thinking a 5x5x10 should be big enough but might stretch it out to as big as 6'W x 5'6"H x 10'L. I'll be towing with a Sienna minivan so weight and aerodynamics are important. Hoping I can start with a landscape trailer if I decide to go with the drop down ramp design and incorporate the built in ramp.
Here's the ideas I'm starting with. I'd really appreciate any feedback I can get. My carpentry skills are decent enough but I have no welding skills so will have to hire that out if needed.