Probably possible but would require a lot more work.
The closest thing that ‘‘will’’ reunite real-time rendering and gpu offline raytracing is the announced Octane render plugin for ue4. Don’t hold your breathe tho because we could wait for a long time before we can use it.
By the way, Octane Render is a more complete gpu renderer than vray. It’s quite powerful. Have a look at F-storm too, it’s in beta and it’s free for now. It’s , imho, the corona of gpu renderer. Very easy to setup.