Like a carbon fiber cylinder that extends back toward the shooter but still allows you to see the numbers. Since the Bushnells are long it would give a closer place to work the parallax ring.
A guy here in California built a home-made one.
As high as many folks mount their scopes, a larger ring in the same design you show with a flange or hub to fix the CF or nylon tube to might work??
Forgive my MS paint drawing but this is the idea: