Maniraiser,
There is a novel trilogy called The Tenth Planet, just so you are aware. Each book is only a few hundred pages, so it's a relatively quick read. They don't call it Nibiru or it's inhabitants the Annunaki, but you'll need to try and make the plot different enough from it somehow if you're serious about writing a novel along these lines.
Good luck! :-)
p.s. It should be easy to just take the basic Solar System model already in US v2.2, and add in a red dwarf still fairly far out in a highly eccentric orbit into the inner Solar System. Put it on a fairly slow setting, and tweak it's orbital characteristics until you are satisfied. Then speed up the simulation. Obviously, since there are near infinite possibilities with it's orbital and mass characteristics, there are near infinite possible outcomes as far as how it alters planetary orbits. With a mid-range quad core system you could probably get around 2,500-3,000 years per day of processing at 1 hour time steps if you turn off ALL the graphical extras, and put it on full screen mode.