National Rosita mandolin
1930s National Rosita mandolin, needs work. $300.
Here's an exceedingly rare vintage mandolin from National Res-O-Phonic. Nearly all vintage National mandolins have metal bodies; this wood-bodied model is the sole exception I know of. I have seen only four examples of it, including this one.
     I'm calling it a "Rosita" because it has similar soundholes to the Rosita guitar also produced by National during this period. Solid wood body and neck were probably supplied by the Regal factory, but the coverplate has the correct National-registered patent numbers, indicating that this was assembled and finished at the National factory.
     There are tons of Regal-made "fake resonator" mandolins that resemble this one but don't have an actual resonator cone. This one does have a cone and National-style biscuit bridge.
     National claims that its current wood-bodied RM1 mandolin is based on a rare vintage model, and that rare vintage model might well have been a Rosita. Like the RM1, it has a wood body and a standard 13.875" mandolin scale, rather than the 15" scale found on metal-bodied Nationals.
     The bad news is that this instrument will need a neck reset to make it play in tune. There's also lots of wear, some scuffing and a chip out of the headstock, but all the parts are there and it just needs a luthier's attention, so I'm offering it as a project. Trapeze-style tailpiece is a modern replacement. Funky, bluesy tone, but a bit warmer than the metal-body Nationals. Serial #1436. 
     $300 plus shipping. Comes with a gig bag or a Johnson semi-hardshell case. See more photos, or for more information.