Designs for Sell?

[Bill Egge]

Does anyone know of some place where I can buy software designs?  

For example, instead of starting a new project from scratch - maybe I could buy a design and then I can change it if necessary.  This would save me time.  

For instance, I had just created a 2 way Network messaging thing where client or servers could notify each other (not just a one way).  It would have been nice if someone had already built something similar.  

Btw - I am not interested in buying code - I would rather build it myself.