Use of Non-Conventional Materials for New Construction

[Pope Lake]

BP, 

Lumber and steel prices are going insane right now, does anyone know of reliable non-conventional building materials that can be used to reduce construction costs? I am currently seeking to build 4 new townhomes in the Birmingham, AL market my goal is to avoid (to the extent possible) using conventional materials like lumber and steel to create more value for my investors. 

I've been reading, and a number of materials have come up so far - insulated concrete forms (ICF), structural insulated panels (SIPs) - and I'm curious if anyone in this community has any experience with materials like these or others. 

Thank you!