Architectural Ceramics for the Studio Potter: Designing, Building, Installing, by Peter King. Excellent resource for making your own slab-built or wheel thrown sink basin. Covers mold-making, draping, making overflow bowls and drains, and throwing a rim. Well-illustrated with good photos.
How to Make a Sink Mold, by an EHow contributor. Tells you how to make a rubber mold, step-by-step, with the intention of casting concrete. Could possibly be adapted for slip-casting with a plaster mold. Or not.
Plaster hump molds, Clayart thread. Various potters discuss how to use them successfully.
Wheel Thrown Sinks, Waterstone Bathroom Sinks. Pictorial guide showing potter Dan Weaver throwing a modern-style bowl/basin.