You mean a tileable texture? That would get rid of the seams, but you'd still have repeats. A good combination might be to get a tileable texture, break up your terrain into sections, and assign a different copy of your texture to it.
Then in photoshop or something, add some variation to the interior of each copy, while retaining the edges so there aren't any seams. Then you're rid of the repetition. Just an idea.