I just went thru this and eventually cobbled together, thru trial and error, a decent customized search facility that includes a product thumbnail in the results.
It would be wonderful if SS provided a cookbook covering each of the three templates. The templates are way too complex for me. A few years ago someone here posted code for placing a divider between each returned result; I was never able to get that to work, for example.
In looking at many Shopsite sites, I notice that few of the small commerce sites bother changing the stock templates. OTOH, many of the larger and nicer sites simply outsource the search function with something like Picosearch.
One of the best examples of what Shopsite's own search can look like is found at:
http://www.gentlemansemporium.com
Jeff at
http://www.ackley-uniforms.com