The vihuela above has a passing resemblance to the "Quito Vihuela" as well. I'm not sure when the Quito was identified as a vihuela but perhaps Papazian was aware of it in the early 1970's...who knows?
Stephen Faulk wrote:It joins at the 8th fret instead of the 11th, that is a big problem for many reasons.
Most early renaissance lutes join the neck to the body at about the 8th - 9th fret so it looks to me like that's what Papazian may have been thinking (I'm just guessing at his thoughts). For the vihuela and early renaissance 6 course lute repertoire, I don't think it would be a problem at all to have the join at the 8th. My main renaissance lute joins neck to body at the 8th fret and for 90% of the entire renaissance lute repertoire including the vihuela, I don't even have a hint of any issue. For some of the later material which appears to have been intended for the longer string length, F or F# tuned lute and joins at the 10th fret, there may be a bit of an awkward left hand movement when fretting the higher notes on the shorter neck instrument but one is probably not going to be playing that repertoire on the vihuela anyways.
The thing that would be the deal breaker for me with this instrument is the fixed frets...there goes all the wonderful meantone temperments!
Present day renditions of the vihuela end the frets at about the 10th fret. And from iconographic evidence this would appear to be historically correct. Often they look like they join the body at the 11th or 12th, but as none of the extant vihuela music really goes higher than the 10th fret it's usually not necessary to continue the frets beyond that.
Check out the work of Alexander Batov for a good indication of what the original designs may have looked like. Alexander has spent a great deal of time and energy researching the early vihuela so I'd venture to say, he's probably the best resource for the instrument that we have today.