Luthier Augustino LoPrinzi started building Guitars in 1969 and his daughter Donna joined him as an apprentice in the early 1990's. They now work out of Florida USA and build Guitars and Ukuleles. They offer well over a dozen models of Ukulele and most come in Soprano, Concert, Tenor and Baritone sizes, on top of the there is a Herb Ohta endorsed Concert model. They have also done some Minis they call Bambinos as well. 

The output seems so great now that I don't think it can just be the two of them but I have no evidence there are more and all of the publicity says it's just them?