When we purchased our 5th wheel trailer, it came with a very nice stainless steel "country" sink. Unfortunately, the cover for the sink was just a cheap piece of plastic. This was a bit disappointing as in a RV, you need as much countertop as possible, and often you see them having a sink cover that can be used as additional countertop.
After a bit of research, I was able to determine that the OEM for my RV was AIA Countertops, and like many of the OEM suppliers, was based in Syracuse, In. So after a few emails, I contacted Andrea at AIA Countertops and was able to order a set of matching solid surface inserts. As they were the OEM for my RV, they had all of the information necessary to make the covers.
AIA Countertops are OEM for certain RV's made by:
This of course is not a do-it-yourself project - although solid surface material (Corian and others) is well machined with basic woodworking tools, I was able to take advantage of having them built for less than $50, which is really not much more than the material would have been for me to order.
And with the split covers, we can cover half of the sink for countertop use, while still making the sink itself accessible.
Oh, that little shark scrubby holder? It stays put as we lumber down the road by using QuakeHold "Earthquake" Putty.
References: AIA Solid Surface - RV Division