I routinely open DNGs processed in ACR as objects so I can go back into ACR to tweak exposure adjustments after have done some adjustments using masks in PS and print a proof. The when I reopen in PS, I still have my PS layers there, and I can keep going back and forth as long as I want (as long as I don't rasterize the object to mess with the pixels).
Is there a similar functionality in LR4, or will it always export to a PSD or TIFF in order to open the file in PS?
Thanks