As a judge, it is very time consuming to go check the weave pole bases all the time if they don't connect in the middle. Most all the weave poles I have encountered have connected in the middle. There is nothing in the rule book about them not connecting and I feel they are more stable if they have some way to connect them.
Sorry I don't really have any vendor suggestions, maybe if we knew where you are, someone could send you in the right directions based on geography.