Does the following work?
Code:
for i in range(0, 24):
t = vrpn.addTracker( 'Tracker0@localhost',i )
s = vizshape.addSphere(radius=.1)
s.setReferenceFrame(viz.RF_VIEW)
l = viz.link(t,s)
#change z value to move sphere closer/farther from view
l.postTrans([0,0,2])
trackers.append(t)
links.append(l)
shapes.append(s)