If memory serves me right, some years ago I heard rumors about developing methods of computing the Casimir force which are rigorous (by the standards of constructive quantum field theory). I become interested in this subject more recently, but it seems there is no way to find it in the flood created by physicists. (I really did not find a single paper.) Does anyone know relevant references?

[EDIT] Now that I think about it, this question may be misunderstood. What I mean are, of course, methods of calculating the Casimir force in nontrivial cases. (Such as complex geometry or two parallel but inhomogeneous plates.) There is a vast physical literature about this.