It has been done, and for various reasons.

While some like the look of wood, others prefer to deocrate with paint. They achieve the same rounded hull shape, of course, and that is what realy matters. Some people put a graphite enhanced layer of resin on the bottom of the hull to protect it from scratches, or in the hope it will increase speed by reducing drag. It looks like black, or dark gray paint. If you are going to do that, I figure you might as well paint the rest of the boat.

One advantage of paint is that it is frequently more durable than varnish, so you don't need to dig out the paint brushes every year. Also, an opaque layer of paint is an ideal UV block, so your epoxy resin is wonderfully protected.

Hope you find an interesting colors scheme.

Should you later change your mind, and decide you prefer the "bright" finish of varnish, you can always sand off the paint. It won't sink in past the layer of resin, so you'll be able to strip it off completely without going into anything structural(like resin, glass or wood). Then put on the varnish.

By the way, I use the term paint rather broadly. You would probably use coverings that were enamels, polyurethanes, or epoxy based, as opposed to latex- or oil-based house paints.

Hope this helps

Paul G. Jacobson