Jim wants us to build him a custom quad and has had lots of input for others on BROL. You can see his goal on his website at http://cyclingexperiences.com/ and his BROL thread. My job is to actually implement his desired modifications at a feasible price point. I'm trying to keep the cost low for Jim, so I'll be working on the design of the project on my own time. I'll post renderings here and you'll be able to see things go from a rough to finalized version.

Jim wants a floorboard on the Quad, so here are some basic ideas of the room that we'll have to work with. There are only a few mounting points, plus it needs to work around the chainline. Oh, and he wants it strong enough to support 200lbs or so, all while being lightweight.

The main obstacle here is going to be trying to make it strong and lightweight.

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Here is my first draft of the outer cage. The cage's main purpose is to provide support for a sunscreen and solar power cells.

My first thought was to use a flexible material that could easily be dismantled and stored in the field, but Jim said that the shape of the cage is of utmost importance, so that was out.

I think that 1/2" aluminum tubing will give us the rigidity and light weight that we need. With the right couplers the cage will still be able to come apart.

I have this setup with 4 different curves and no straight pieces.

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I plan on coming up with an entire roll cage structure first. Once the mounting points and method is decided it will give me more structure to attach a floorboard to. I'd like to avoid attaching the roll cage to the boom, but I may need to do it to get the front end solid.

Here is the magic piece I think will work to hold the cage all the way around to the frame.
2 up front and 2 in the rear.

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This shot shows the cross arm with a clamp and the bottom mid section cage support.

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The cage is coming together nicely. I have some preliminary couplers for the perpendicular tubing sections.

With the front sidemembers of tubing we won't need to attach anything to the boom. The lateral stiffness will be very good, and can easily be augmented if needed by a triangular brace between the top rear support and the nearby side supports.

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If I can find some premade couplers that will suit the application it will probably be cheaper, but here is what I am envisioning at least for the perpendicular sections.

The main reason I want something like this is to not have to drill holes through the tubing allowing the crossbar spacing to be moved if necessary to accomodate the widest variety of covering solutions.

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The lower crossmember here is for floorboard support. Between that and the frame we should be able to hook a floor up.

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While I'm waiting for the SON generator hub from Jim I figure I might as well start filling in the gaps to see what it might look like with some covering.

I figure a flexible cloth material on top so it can be moved and 5-6mil polycarb on the front and rear.

Still need to figure out the floor.

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Here is a top view to give you an idea of the room we have to deal with.

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Here is a side view to give you an idea of the room we have to deal with.

This is my model of the SON hub that Jim sent me. An accurate model will let me figure out exactly where it needs to go.