Adding more r/d in a glass laminated bow would require a new form.
I'm not sure if a professional bowyer would want to do that to suit a single customer's wishes because it's not simply just building a new form. It also entails making a couple bows to determine the appropriate lamination thickness in order to hit a desired draw weight and figuring out the intricacies of tillering it to shoot as desired.
Your best bet would be to look for other bowyers that are similar to the Wallace, but with a little more r/d.