I'm definitely interested. Post back here when you get the details.
I did a quick google and there appears to be a number of different sources online. It may be easier to send samples of MX brown springs to some of these companies and get estimates for cloning the spring, rather than designing a new one.
Also, I think that it's likely that someone already has a large stock of springs of suitable specifications already. The springs seem to be a standard size - it's just a matter of finding the right supplier.