Mark if your not in a rush on this I am planning on taking some time out of my schedule over the next fiew days to compose an article on regiums based upon my readings.
A good book that has a very good chapter on refugiums is Reef Inverts by Fenner and Calfo (sp?). it can be found in our saltwater library.
the wet/dry is not exactly the best solution for reef tanks because they harbor nitrates more than a deep sand bed and live rock filtration.
Refugiums can be built out of anything from a rubbermaid tub to a small aquairum and can hold different items depending on what your goal is.