This coincidence is rather striking and has been the subject of much speculation, though nobody has been able to make anything useful come out of it. If this theory manages to predict this relation within the created universe, that would be evidence for the theory.
Also note that if there are universes inside black-holes in our own universe, they have much less mass to play with.
The best this theory (that, unless it can be tested, may not deserve to be called one) has going for it is that the math is right. And since I haven't seen it, I can't say that either.
National Geographic is not the best source for news in Physics or Cosmology.
If you assume that the next approximation to Newton's gravity equations are similar to Maxwell's equations (thereby introducing a secondary field analogous to B, the magnetic field) then you can do back of the envelope calculations that get you interesting results including this one - i.e. our universe's radius is of the order of Schwarzchild's radius of a black hole of the mass we estimate, together with the acceleration equivalences under that condition. By that I mean - the two situations of you accelerating w.r.t the rest of the universe and the rest of the universe accelerating w.r.t. to you are physically indistinguishable. You can get that for rotation (in which case the B analog gives you Coriolis force) and for linear acceleration as well. I think in these limiting calculations you get some constant factors wrong (like the Newtonian escape velocity calculation) but the order turns out ok.
This "analog of B" is called the "gravitomagnetic field" (http://en.wikipedia.org/wiki/Gravitomagnetism) and NASA's GP-A and GP-B probes (http://en.wikipedia.org/wiki/Gravity_Probe_B) are for measuring this effect near earth.