It's important to note that in order to create a sugar-cube-size volume of quark-gluon plasma, you'd need to already have 40 billion tons of uncompressed matter, or the equivalent energy. Plus, a particle accelerator large enough to smash it all together.
And if you already have that much matter, all the insane gravitational consequences (Sun crashing into Earth, et cetera) would already have happened. Thermodynamics, baby - you can't get something from nothing.
It's like a system's orbit. If a star of mass greater than 20 solar masses was instantly compressed to its schwarzchild radius, the planets orbiting that star wouldn't get sucked into the black hole. The gravitational effects would still be more or less the same at great distances. Of course, the star would really have to go supernova first, either melting or pushing away its orbiting planets, so such a scenario would never actually happen.