Finding small, scholarly publishers who publish eclectic and rare bits of liturgical history, or who republiish some of the classic texts has always been something I've enjoyed.
One publisher I neglected to share in our list of links, is Gorgias Press who publish a number of books related to Eastern Christianity. They also have a Liturgy section which includes books like F.E. Brightman's compilation of Eastern liturgies, as well as other non-Byzantine (i.e. Oriental) liturgical items that some may find of interest here.