There are some 2,000 Jovian Trojans, and four Neptunian ones (so far). There are two Tethys Trojans (Telesto and Calypso), and one Dione (Helene). I'm pretty sure it's easy to show that any Galilean (Io, Europa, Ganymede, Callisto) Trojan could not be in a stable orbit. And neither would any Mercurian, Venusian, Plutonian, or any of any smaller body (Himalia, for example, or Phobos). But what about the larger bodies - are Saturnian or Uranian Trojans unstable (due to Jupiter and Saturn, respectively)? Trojans of our Moon? Titanian or Tritonian (sp?) Trojans? Simulations - digital orreries - are now likely good enough to test stability (within Newtonian gravity anyway; maybe GR would need to be included for Mercury or Venus?); but could some sensible constraints be put on these analytically?