  In this paper we use techniques from convex projective geometry to produce
many new examples of thin subgroups of lattices in special linear groups that
are isomorphic to the fundamental groups of finite volume hyperbolic manifolds.
More specifically, we show that for a large class of arithmetic lattices in
SO(n,1) it is possible to find infinitely many non-commensurable lattices in
SL(n+1,R) that contain a thin subgroup isomorphic to a finite index subgroup of
the original arithmetic lattice. This class of arithmetic lattices includes all
non-cocompact arithmetic lattices and all cocompact arithmetic lattices when
$n$ is even.
