You can access all objects from the scene by its name:
import GameLogic
scene = GameLogic.getCurrentScene()
obj=scene.objects['ObjectName']
To access the vertices:
import GameLogic
scene = GameLogic.getCurrentScene()
obj=scene.objects['Cube']
mesh = obj.meshes[0]
for v in range(mesh.getVertexArrayLength(0)):
vert = mesh.getVertex(0, v)
print( "%d,%d,%d" % ( vert.x, vert.y, vert.z ))
print( dir( vert ))