Hey David,
I'm a SUAVE user and I'm working with plot_vehicle too. It seems as though the fuselage gets displayed only if it is segmented. You can try plot_vehicle in the tut_C172 in which the fuselage is well-segmented. Apparently, more detailed the segments are, the better.
Discretization in x-direction (windward direction at AoA=0) happens only with segmentation, while tessellation count is designed for y and z directions for fuselage.
Let me know if you find a work around.
I'm also interested to know the inputs from SUAVE team on this.
Best,
Jeswin