So I just realized that Jardine/Supertrapp is located not far from where I live.  I wonder if they would be willing to make a new style of exhaust for the GS.  Something a little more extreme than what they currently have.  I would let them use my bike as a test subject if they are willing.  Imagine a GP-1 style for the GS!!  That would be so cool.  If they are not willing, I'll see if they would at least build me a carbon canister for the current system they carry. 

They are not fully in production of the Jardine yet. They still have a mess from buying the company and moving the assets. If you could get them to make you an exhaust, it probably would be more expensive than a GS500.

I have been in contact with them as recent as yesterday about Jardine RT-1 parts.

They are still not up to full production. They do have systems. The 18-QMI-2 quiet inserts are not yet available.
The 12-QMI-2's are available. I asked the difference and Gerry at Supertrapp told me. So I can get a 12 type and drill extra holes with a drill press or enlarge the hole to make it work; Her information:

"They both will fit into your muffler but if you use the 12-QMI2 for your RT-1 exhaust it may be too restrictive, the out let opening on this one is .75
The out let of the 18-QMI2 IS .875."