Greg- the Nudura t & g is EPS, and not the best choice for ceiling insulation during the cooling season since it's R value drops signficantly with rising temps- you'd be better off with your buddy's ccSPF there (at the same rated R.) EPS works better under slabs and on foundation walls where the "hot" side isn't above room temp. EPS is used as roofing insulation all the time, but from a design point of view it's wise to derate it's R by ~15-20% in those apps during the cooling season- more if you aren't installing a radiant barrier or "cool roof" materials on the exterior. Type-I & II EPS runs ~ R4/inch at 40F, but will be ~R3/inch at 100F, even lower as the temps run higher See: http://www.transconsteel.com/products/ultraframe/docs/Other_Properties_of_EPS.pdf

Would option #5 (SIPs) be an extra $3-5k including labor? I don't think comparing stick vs SIPs is possible without considering the vastly different time, labor, quality, durability, complexity and risk.

We will be doing our first owner-builder home this year, and I've done a ton of research and I'm confounded by comparisons that don't include time, labor, quality, durability, complexity, and risk. We're evaluating everything in this way. The way I see it SIPs is the best solution for owner-builder because except for material cost, it is same or better in all the other aspects.

[ Disclosure: I have no relation to SIPs or the construction industry. I'm a 'civilian'. ]

you are correct, all prices I listed are for materials only.  And actually, the SIPs numbers I posted here are no longer valid.  They had a pretty large price increase, and instead of the 3-4k, its more like 6-8k now.  If I DIY ICF, (vertical form, Hobbs) then its around 7k more.

However having modified my design based on pricing and efficiency, I think I have settled down on a double stud wall concept, although staggering the 2x4 on 24" centers using 2x8 top plates.  I keep going back and forth with what to sheath it with.  1.5, even 2" XPS seems flimsy on 24" centers.  I am leaning heavily on ZIP sheathing which I think will give me a better air barrier then the XPS will. Plus I like the nail base instead of 24" centers. I am not so sure the thermal gains in 1-1.5" XPS will be that much greater then the advantages and higher air sealing the ZIP offers.  Changing my walls r from 30 to 33 resulted in about 300 less BTU requirements.... Fill the 7.25" wall void with blown fiberglass (they are claiming around a 4.2/inch) should give me a pretty tight medium high r thermally broken (with exception of at the plates) assembly. This is actually pricing out less then advanced framed 2x6 with 2" XPS.

SIP prices doubled in a month? waaa!

no, their price didnt double, rather the added cost of them did.  THey went from around 7500 to about 11k(thus adding around 6k instead of 3k)