Miami won't do it. If they don't re-sign Marion they will probably want to go after Brand. Taking RJ in a S&T takes away their cap space and prohibits them from going after Brand.
I sincerely doubt this will happen. Although, on the wild assumption that this did happen, all it would do it put the Nets back into the 2nd-round-and-out zone they were in the last two years. They wouldn't be strong enough to compete in the present vs. Celtics/Pistons, and they wouldn't be strong enough to compete in the future vs. young teams like Philly/Atlanta. It'd basically make the Nets equal to the Raptors.