A friend of mine, a convert Catholic family in fact, is by trade a Catholic proprietor of scholarly, scarce and fine books; books with a particularly Catholic bent to them, and more often than not, directly Catholic.
He has one of these delightful inventories that he keeps stocked that includes all sorts of Chesterton, Newman, Belloc, Dawson and C.S. Lewis; one also finds liturgical books, patristics, literary classics, all sorts of theology and Church history.
His editions are particularly hardcovers, but range from paperback to antiquarian.
It's also worth noting that he regularly drives to the United States some that American customers can receive domestic shipping rates.
He has an ad up in the sidebar here at the NLM, which if you click to, will take you to a searchable inventory: Cardinal Books -- they eventually hope to bring all their inventory over to their own site.
Now let me tell you something: he has a fair bit of Catholica that he is preparing to put in his inventory, so if you don't see a title you are looking for, make certain to ask.
Case in point, I was visiting him the other day, and he has an immaculate copy of "The Roman Breviary" published in 1964, being the Christine Mohrmann translation of the 1962 Breviarium Romanum into English. He also has a copy of Fortescue-O'Connell, a copy of Cabrol's "Liturgical Prayer: It's History and Spirit", a copy of the Franciscan Ceremonial (Caeremoniale Romano-Seraphicum) and so on.
He carries quite a bit of Catholic philosophy (Pieper, Maritain, Gilson and so on) and also has such delights as signed copies of Chesterton works.
Do take a visit and make certain you tell them you heard about them on the NLM.