your question about cross talk is a valid concern, my 2 cents on this
are that any noise generated out of the power supply sitting across
the center taps assuming no capacitors to chassis ground are present
at each center tap, would cause us EMI headaches way a head of any signal interference.
please keep the filter needed to pass EMI radiated and Conducted testing
out of the system in mind.also please keep in mind that the center tap
at lower frequencies has good common mode tolerance per the graphof my
last presentation (at frequencies below 1MHZ or so the receiver does not suffer). of course I may be missing your point....