[SunkenCiv]

And perhaps a ring. I'd not be surprised if more moons / moonlets are found. Boring old tiny little Pluto will wind up one of the most interesting, precisely because of where it is and (by 2012) its many siblings (such as Brown's Planet, Quaoar, Sedna, 2003 EL61, 2004 DW, and those to come in the next six years).

[to all]

The satellites of Neptune and the origin of Pluto
Authors: Harrington, R. S.; van Flandern, T. C.
http://tinyurl.com/qsozh

[SunkenCiv]

• A Dynamical Study of Escaped Satellites of Neptune
  Robert S. Harrington, T.C. van Flandern
  
  September 1977 -- It has frequently been suggested that Pluto may be an escaped satellite of Neptune. The idea that Neptune has suffered some disruption of its satellite system is supported by several anomalies. For example, Triton is the only large or close natural satellite with retrograde motion, and the eccentricity of Nereid, 0.76, is by far the largest value for any solar system satellite. Tidal escapes are uninteresting because they cannot account for the the large eccentricity or inclination of Pluto, or for the condition of Neptune's two remaining satellites. We conclude that the most viable explanation for the hypothetical disruption is the passage of a large mass close to Neptune. We present the results of a series of Monte Carlo experiments, with which we have tried to set limits on the circumstances surrounding such an encounter. The experiments show that orbits very much like those of Pluto, Triton, and Nereid can result from such a close encounter of a massive body with Neptune. added Saturday, October 22, 2005
  
  [the obvious problem with the idea at this point is that there are so many other known, large bodies in the outer solar system; if Pluto was indeed a former satellite, one might ask if the disruption of Neptune's satellites was due to the capture of Triton; TVF doesn't like capture unless there's a second larger body involved]