Never tried it, but I have done several projects with the mix Jerry described. In theory, a water-based finish over oil should work, just like you can put a latex top coat over an oil-based primer. I have used oil-based stains on oak and pine, and then used a water-based poly for the finish, but stain and BLO is not really comparable.
I suggest trying it out on a piece of scrap.
BTW, I've also applied BLO (thinned) on by itself, then topped with the oil-base poly. There doesn't appear to any difference compared to using the mix, although with the mix the result looks more even and smoother.
Bas.