Need a custom fabrication for bike accessory done - who does this?

I am hoping someone on here can point me towards someone willing and able to manufacture me an accessory for my longtail based on a recent product that xtracycle came out with.

We are loaning our current child carrying cargo bike out to a family with a much smaller baby than my son (he is 2). He has outgrown his front mounted seat and I would like to move him to the rear of my Yuba Mundo where my 6 year old currently rides stoker. We've looked into the few bike seats that are compatible with the bike and I just don't think they are going to work for us given that towing my daughter's bike in addition to cargo is hugely important to us and baby seats take away most of that capability.

In November/December, xtracycle came out with the Hooptie (can't say that with a straight face ever) that is a child handlebar/roll cage the circles the entire flightdeck of the bike. Here is a link

http://www.xtracycle.com/cargo-bicycles/xtracycle-cargo-accessories...

The Yuba is wider and longer than the xtracycle in general. I'm hoping to find someone who can price and make this for me. If I can't find anyone, we might just go with the xtracycle model but that's not my first choice.

Anyone? Not sure where to start with this but I am on a time schedule.