This question is what lead me to ask this. Strong force between quarks that are out of causal contact and my understanding of the standard model is that the answer is no - but the standard model isn't necessarily absolute.
Like, for example, when the strong, weak and electromagnetic forces combine at some obscenely high energy state - do solo quarks become possible?
If this article is correct, I'm guessing the answer is yes, or, at least, maybe: http://physics.aps.org/articles/v7/61 but the article is for Top Quarks.