I need this type of clay brick or similar, known as thermo block in some places Where in the U.S. can this be bought?:

more infos here but there are many other manufacturers worldwide. I just can't find one in the U.S.: http://www.mladost.co.rs/eng/termo_blok_33.html

That is from a European core wall. I have never seen them here but an alternative to it could be "Ytong" sold in the US by Hebel.......

http://www.hebel-usa.com/en/content/blocks_1341.php

It is an insulated, air entrained concrete block, very light and structural. Used for decades in Europe.

thanks Mike
I know that type of product, too, I wasn't aware they sold it in the U.S. though.
I'll try to get in touch with them
thanks!

If you are close to the Mexican border you can get this from Mexico.