A close approximation is fine.

I think the color images we have enjoyed of Saturn from Cassini are very close to "true" color. Similarly, the common images of Jupiter, Uranus, Neptune, and many Mars images are more than likely quite accurate, too. There aren't many natural color images of Venus, but I've seen one Galileo image for Venus that is probably close enough. There are images of Mercury that are probably correct, enough so that most of us here would likely agree upon it. Earth is certainly not a problem.

The Sun presents a little more of a problem, as most do not have a clear onderstanding as to its natural color. Some modern textbooks, however, do state the Sun as being a white star (e.g. Jeff Hester, et. al.). From space, it appears blinding white, which is not an indication of its natural color as seen at a properly attenuated level for our vision, yet since it appears mainly white overhead, and obviously white in space, why not white in a mosaic, even if the publisher doesn't really know just how likely white it really might be?

I've done one, but I am not the best person, especially on my list, that should be offering it. My hope is that someone has gone to the trouble to offer such a mosaic. If none exists, maybe it would be nice to add that to the IYA presentations for next year since it was officially 400 years ago that the colorful surface of any planet, excluding Earth, had ever been observed.

Earth-based observations seem pretty close to the color as seen in space imaging, but they can be tweaked by bumping the colors in proportion to the known losses due to atmospheric scattering.

However, since all of the planets have been imaged with cameras revealing natural color, supposedly, why have I not seen one by now? Since many here have better access than I, then maybe several exist. I'll be glad to pay-up, and its not even a bet.

I would expect the vast majority come pretty close.

I'm not needing perfection, but something close.

Most posters are pretty close, but usually get Venus and the Sun wrong.

Notice that this poster comes close with all of them, but Venus. The Sun is pretty close. [I'm not crazy about he rings around Uranus, but that is beside the point.]

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Lighten up! This is a stellar board! Author: duh.

"The Sun, with all the planets revolving around it, and depending on it, can still ripen a bunch of grapes as though it had nothing else in the universe to do..." Author: Galileo supposedly.