One can look at the implications of CSB for low-energy effective field theory and the picture that emerges fits well with Nf=Nc SUSY QCD. So as far as I know there is nothing wrong with low-energy CSB. Also, the main reasons why we chose SU(3)^3 are one-loop gauge coupling unification and Landau poles. The quick way to see that gauge coupling unification occurs is to consider SU(3)^3 as a subgroup of the GUT gauge group E6, thus leading to conventional gauge coupling unification. We did not spend time on that nor on E8, considering instead D-branes in Type II as the origin of the SU(3)^3 gauge group, but the extra SU(3) is strongly-coupled and does not unify with the three SU(3)s, hence trinification rather than tetranification.

Cheers.
By the way, no need to apologize, Jeff is the usual nickname for Jean-Francois.

Are you saying that CSB and ISS are compatible? I thought that CSB required a complete departure from low-energy effective field theory while ISS required to take it completely seriously.

The Pyramid Scheme quiver is very interesting. I wondered whether it has a natural embedding into E8 which has a SU(2)^4 subgroup. But it probably doesn’t because the trianons do not appear in the decomposition of 248, and even the “27″ appear thrice.

Or maybe one should use a non-fundamental rep of E8? Their dimensions are pretty high.

It’s interesting why you didn’t call it Tetranification instead of Pyramid Scheme.