you'd need a lotta luck if you assume the center of the boundingbox at xform -q -ws -t
:]
you can get everything directly from a transforms attributes: there is:
pCube1.boundingBoxMin // <-- float array
pCube1.boundingBoxMinX
pCube1.boundingBoxMinY
pCube1.boundingBoxMinZ
pCube1.boundingBoxMax // <-- float array
pCube1.boundingBoxMaxX
pCube1.boundingBoxMaxY
pCube1.boundingBoxMaxZ
pCube1.boundingBoxSize // <-- float array
pCube1.boundingBoxSizeX
pCube1.boundingBoxSizeY
pCube1.boundingBoxSizeZ
pCube.center // <-- float array
pCube.boundingBoxCenterX
pCube.boundingBoxCenterY
pCube.boundingBoxCenterZ
everything you need :]