Sorry for the late reply, this forum somehow doesn't notify me of replies, although I'm subscribed to the thread.

Thanks for all the feedback!

- Elliptical Fillets are basically the same when it comes to tangency as circular ones, just with two different radii IMO? Or am I off the mark here?

- Well, if Catia is that expensive, maybe it does good fillets ;-)

- I'm sorry but I can't post anything, it's under NDA.

- I'll not go near anything Autodesk if I can avoid it.

- While I have a modo 601 license, I'm not too hot about that company/software either. ;-)

But the idea to delete the circular blend and then replace it with a surface blend could be at least interesting to try. I guess it would end up being a lot of work, especially at the corners.

Well, I'll see what my customer can do in Catia and if all else fails, I'll do it in polygons with Subdivision Surfaces before I get lost in too complex a NURBS setup.
This would have some other benefits as well like a more even mesh and easier UV-Mapping.

Edit: Just checked on Spaceclaim and VSR, but that is all outside of the margin of this job pricewise.

Thanks again!

Tom