There is currently no built-in way to access the vertices, but you can save the model to the STL format, which is a simple text format that contains all the vertices. Here is some sample code allows you to iterate over the vertices:
Code:
import viz
viz.go()
model = viz.add('logo.ive')
def getVertices(node):
"""Iterate over vertices"""
node.save('temp.stl')
vertices = []
with open('temp.stl','r') as f:
for line in f:
s = line.split()
if s and s[0] == 'vertex':
yield float(s[1]), float(s[2]), -float(s[3])
verts = list(getVertices(model))