Sure, I have plants that are a little bigger than that, in pots that are the same size. They're getting really close to being rootbound though, so you'd have to be careful to not let them get much bigger that that.
I don't normally let them get that big in the 1 gallon pots, those are leftover plants that I couldn't fit in the bloom room, and haven't had the heart to chop down, yet.LOL