Just read about a product called FLEX-MOLD on the Pearson-boats group.  It looks like a clever product that may be used to match the gelcoat pattern when doing repairs on non-skid deck surfaces.  
Here are links for the product and a pattern that has been recommended for Pearson boats.  I have no experience with it yet but I wanted to document it here to share the information for future reference. 
Jamestown Distributors + VideoFLEX-MOLD Pattern