  For every finite graph $\Gamma$, we define a simplicial complex associated to
the outer automorphism group of the RAAG $A_\Gamma$. These complexes are
defined as coset complexes of parabolic subgroups of $Out^0(A_\Gamma)$ and
interpolate between Tits buildings and free factor complexes. We show that each
of these complexes is homotopy Cohen-Macaulay and in particular homotopy
equivalent to a wedge of d-spheres. The dimension d can be read off from the
defining graph $\Gamma$ and is determined by the rank of a certain Coxeter
subgroup of $Out^0(A_\Gamma)$. In order to show this, we refine the
decomposition sequence for $Out^0(A_\Gamma)$ established by Day-Wade,
generalise a result of Brown concerning the behaviour of coset posets under
short exact sequences and determine the homotopy type of free factor complexes
associated to relative automorphism groups of free products.
