It's an 18inch. Spec wise it's factory standard with the changes mentioned to make it more suitable for ultra distance:
You should be able to get a better idea here..
http://salsacycles.com/bikes/el_mariachi/Changes:
Ergon Handles
Suspension seat post
XT pedals
Tri Bars if you need them
I can get some photo's of the bike this week, it's in for a service and general tidy up after the Tour Divide.
Where do you live?