If you read this history of the Church of the Larger Fellowship, you'll get the impression that the Universalists had a scant history of extra-congregational ministry and what it did have was only tacked on to the better-known Unitarian Church of the Larger Fellowship to form the body we know today. (More about the National Memorial Church it mentions later, since I think that's a reference to the Universalist National Memorial Church, which I once pastored. In which case, the article is partly incorrect.)
But the Universalist contribution isn't minimal. The history and polity of the Convention Churches is, however, one of those little-explored areas of our traditions. The more I examine it, the better I feel about the CLF, and the prospects and propriety of having other ministries with a similar model. I no longer think of it as a "legal fiction" in congregational polity, in part because it works so well with Universalist (if not Unitarian) polity.
After 1870 -- the high-water mark for Universalist institutions -- and certainly in the 1880s, some of the smaller or more diffuse Universalist state conventions created "Convention churches" to serve Universalists that were not a part of a local parish. (I have a list somewhere.)
It's hard to say what kind of services these members received. This article [2009. Archive.org cache of defunt Geocities service] suggests the Convention Church was the institution that might have run a "post-office mission" -- not unlike the CLF today. (Though the Universalist press was more vital then than the Unitarian Universalist press is now, so one could have had a steady stream of sermons, liturgical material and inspirational literature and not be a member of any organization. Newspaper subscriptions -- and people had multiples subscriptions! -- is what I think accounts for the wildly inflated membership numbers we sometimes hear, such as those claiming that the Universalists were once the sixth-largest denomination.) Perhaps more pressing to a denominationally-minded age, the Convention Church gave isolated Universalists an orderly place to "hold their membership." Convention Churches had voting representation in the state conventions. And like General Assembly today, we know that nineteenth century Universalists enjoyed conventions as venues for good sermons and socializing.
But it's important to understand where in Universalist polity this impulse comes.
Mature Universalist polity recognized that fellowship ought to be maintained at the most local possible setting, that both churches and ministers were subject to fellowship and that a condition of fellowship
was the profession of a particular profession of faith. (So that ministers and, collectively, churches were subject to professing the Winchester Profession, but not individual church members, unless the congregation itself made that a condition of membership. Something to ponder in the current Principles and Purposes revision study.)
The most usual place for a church or minister to keep fellowship was the State Convention. Most states had them, though their size and ability to function varied remarkably. But at the very least, they held meetings and made decisions about fellowship. State Convention were organized sui generis and were received by the General Convention if they followed established rules (and were rebuffed, in one case at least, if they didn't).
The General Convention, which met every other year, mainly considered projects and policies which were of general importance or were larger than a single state convention's work, like the funding of the Southern Missionary, Quillen Shinn, or the seminaries. But it also extended fellowship directly to churches and ministers that were not within the boundaries of a State Convention. (This Central Fellowship Committee, which also transfered ministerial fellowship between State Conventions, probably gives more to the current Ministerial Fellowship Committee than any other entity.)
So follow me one more step: the Convention Churches act in a corresponding way to provide fellowship to (lay)persons within a State Convention in unorganized areas, just as the Central Fellowship Committee provided fellowship to ministers in states without conventions. (It begs a question, for which I have no answer: ought a Convention Church allow into membership a person residing in a town which had a Universalist parish? So far, I have found no working documents for any of the Convention Churches.)
The experiment in Convention Churches "went meta" with the formation of (what seems to be) a national Convention Church. At the 150th anniversary of "the founding of Universalism in America" in Gloucester, Massachusetts, in 1920, there was at the celebration in Gloucester, Massachusetts, "Memorial and Consecration Service: Reception of Members into the Convention Church." (1770-1920, from Good Luck to Gloucester: The Book of the Pilgrimage; Being the Record of the Celebration by Means of a Great Pageant of the One Hundred and Fiftieth Anniversary of the Landing of John Murray, His Reception by Thomas Potter, and the Preaching of the First Universalist Sermon at ... by Frederick Adelbert Bisbee. Murray Press, 1920, pp. 72-3.)
I'm not sure what these fact mean in practice. By the 1920s, Universalist institutions began to contract and collapse. And how many of these Convention Churches were more than the paper they were written on? That, and the tiered system of Universalist polity has been collapsed into a single level. One fellowship for congregational membership; one fellowship for ministers. And I wonder if that's not hindering our growth.
But the Unversalist models show there are imaginative ways to organize churches, now especially when the cost and speed of communication has never been cheaper or faster. The Church of the Larger Fellowship and its Church of the Younger Fellowship aren't the only possibilities. What they could not, we can, if only we imagine and act.