I think everyone has gotten used to flying the 206 from the right seat. I used to until I started working for a company with a 206 with left side controls (there are actually three of them out there with one time STC's). Now I'm hooked on left seat PIC.
Gordy, I'm afraid you might be right when you say no one will be interested. But once you go left, you never want to go back! So if you're on a fire this summer and see some yahoo flying around on the wrong side of the heli, stop by and say hi.
I'm still going to go forward with my design either way, I just won't spend the time and money getting a full STC if it's not gonna sell.