timberframe redundancy

With SIPS able to bear floor and roof loads I would like to begin a discussion regarding the use of timberframe as a non redundant structural system.

Could you be more specific about your point? There are applications in which a SIP system can stand alone, others in which the timber frame does just fine by itself (without a load-bearing enclosure system), and still others in which a combination of the two is essential to achieving adequate performance. Also, most often redundancy is a good thing and need not be unnecessarily expensive to achieve.

Take for example a typical timberframe endwall - lets it has 1000 bf or more of lumber in it and costs $10,000. Clad that with sips and you have an expensive wall. The cost to traditionally frame the endwall with 2x6' @ 16;' o.c is much less and this conventionally framed 2x6 wall can bear the timberframe floor joists and purlins easy enough.

The question would simply be - what upcharge is being paid for timberframe and sips?.. and is it worth it?

To a similar degree this woul;d apply to conventional perimeter walls.