Hello from six years ago. 
And six years on this still either stops me from continuing with Rhino (unfortunately we no longer have Alias licenses at work, but we do have NX which can also smoothly blend) or forces me to waste an incredible amount of time. Just today I ran into this today again. Plus, Rhino even further sabotages you by converting your single surface to a polysurface when all you want is just a little help with even the first two rows of CVs:
taper.3dm (229.8 KB)
Great example of this and this. I guess now we continue with this.