  We present a novel method to obtain type IIB flux vacua with flat directions
at tree level. We perform appropriate choices of flux quanta that induce
relations between the flux superpotential and its derivatives. This method is
implemented in toroidal and Calabi-Yau compactifications in the large complex
structure limit. Explicit solutions are obtained and classified on the basis of
duality equivalences. In the toroidal case we present solutions with N=1 and
N=2 supersymmetry and arbitrarily weak coupling. In Calabi-Yaus we find novel
perturbatively flat vacua, as well as solutions with non-zero flux
superpotential and an axionic flat direction which represent a promising
starting point for de Sitter constructions from non-zero F-terms in the complex
structure sector. The higher order (perturbative and non-perturbative) effects
that can lift these flat directions are discussed. We also outline applications
in a wide variety of settings involving the classical Regge growth conjecture,
inflation and quintessence, supersymmetry breaking and F-term de Sitter
uplifting.
