Which begs the question: what principals would allow such a device to operate?
As already demonstrated certain sorts of fluctuations and effects at the quantum level can have direct and widespread consequences for macroscopic objects. And one member of a virtual particle/anti-particle pair may be culled off allowing the other to become an entelechy. It seems to me that a way only need be found to link these two effects together in an auspicious manner suitable to producing the particular macroscopic systems desired.
Similarly, other sorts of virtual entity/anti-entity pairs might be conjectured to exist but which normally cancel each other out with a net of zero effect on the universe. The trick would be to would be to cull the anti-entity while allowing the desired entity (or it’s component parts, or components which might give rise to such an entity) to escape into the universe.
One problem that may arise with this sort of process is that quantum level effects may take circuitous or otherwise undesirable routes to propegate their effects at the macroscopic level (ie. a “butterfly effect” type scenario). And basically the more particles involved (say an entire body vs. a few atoms) the more difficult it would be to predict and control the propegation of the effects.
Fortunately, there may be a solution of sorts to this challenge. As proven with the creation of Bose-Einstein Condensates, under certain circumstances a large number of particles can act as if they were a single entity. Having a large number of particles (or perhaps “clusters of precursor particles”) able to spring into existence as a single entity would simplify matters.
There may potentially be some odd issues with the manner in which Heisenberg’s principal of indeterminacy would or would not function when allowed to apply at the macroscopic scale on such massive quazi-fundamental particles. But there may be some ways around the more sticky (pun intended) aspects of this issue through the use of intentional quantum entanglement.
The only real remaining obstacle is that Bose-Einstein Condensates technically only exist at extremely low temperatures and when using homogeneous groups of particles. If a means can be conjectured and tested to temporarily create heterogeneous composition condensates with single-particle waveform properties then I think we could well be in business.