Classical guitar teacher in France (Nantes), I have also a strong attraction for early instruments, Renaissance and baroque in particular.
I play (since one or two years... so I try for the moment!), renaissance guitar, cittern, guittern, lutes 8 and 13 courses, vihuela, mandora, baroque guitar, theorbo, romantic guitar, classical mandolin and different other guitars!
that's right, this is a steel stringed instrument, that is very common in Brazilian folk music.
I recorded Sanz's Canarios on the "Brazilian viola" that we call in Brazil as "viola caipira" (that means: "country viola"). I have made a domestic recording of other Gaspar Sanz and Manuel Alvarez (Guatemalan composer from 18th Century) pieces, but the sound is no good. I intend record it in a professional studio, but I wait my luthier's new viola for these recordings.
Brazilain viola was derived from baroque Portughese guitar and from Portughese viola. On my page, you may see some photos of 18th century Brazilian steel stringed violas.
By the way, your photos are very nice. Beautiful instruments.
I visited your page "http://guiros.jimdo.com". This is marvelous! If you want, I may send to you a photo form Brazilian country viola, back and front.
I lived in Paris for one year, and "je parle français" if it is better for you.