import Blender
ME=Blender.Object.GetSelected()[0].getData()
A=ME.verts[0]
B=ME.verts[1] 
for percent in [10,20,45,75]  :
  C=Blender.NMesh.Vert()
  for n in [0,1,2]:
     C.co[n]=A.co[n]+(B.co[n]-A.co[n])*percent/100.0
  print C.co
  ME.verts.append(C)
ME.update()

import Blender 
me=Blender.Object.GetSelected()[0].getData()
a=me.verts[0].co
b=me.verts[1].co
for percent in [10,20,45,75]  :
 v = a+(b-a)*(percent/100.0) 
 v=Blender.NMesh.Vert(v[0],v[1],v[2])
 me.verts.append(v)
me.update()

import Blender 
me=Blender.Object.GetSelected()[0].getData()
a=me.verts[0].co
b=me.verts[1].co
for percent in [10,20,45,75]  :
 v = a*(percent/100.0)+b*(1-percent/100.0) 
 v=Blender.NMesh.Vert(v[0],v[1],v[2])
 print v
 me.verts.append(v)
me.update()

import Blender
ME=Blender.Object.GetSelected()[0].getData()
A=ME.verts[0]
B=ME.verts[1] 

x1=A.co[0]
y1=A.co[1]
z1=A.co[2]

x2=B.co[0]
y2=B.co[1]
z2=B.co[2]

for n in range(1000):
  x=(n-50)*0.05
  y=((y2-y1)/(x2-x1))*(x-x1)+y1
  z=((z2-z1)/(y2-y1)*(y-y1))+z1
  C=Blender.NMesh.Vert(x,y,z)
  print C.co
  ME.verts.append(C)

ME.update()