We consider aspects of Chern-Simons theory on L(p, q) lens spaces and its relation with matrix models and topological string theory on Calabi-Yau threefolds, searching for possible new large N dualities via geometric transition for non-SU (2) cyclic quotients of the conifold. To this aim we find, on one hand, a useful matrix integral representation of the SU (N ) CS partition function in a generic flat background for the whole L(p, q) family and provide a solution for its large N dynamics; on the other, we perform in full detail the construction of a family of would-be dual closed string backgrounds via conifold geometric transition from T * L(p, q). We can then explicitly prove the claim in [2] that Gopakumar-Vafa duality in a fixed vacuum fails in the case q > 1, and briefly discuss how it could be restored in a non-perturbative setting.