we had worked with a customer on a nearly identical scenario. The customer did what you were considering and saw no measurable improvement. The two domains in question were bike.com and beyondbikes.com. At the time the consensus was that "most" of the link juice and trust would get passed. After about 9 months, the reverse was tried with horrible results. Just about all rankings were lost. My advice would be to manage the properties separately if google ranking factors are top of your metrics.
