With the demise of Penn Lyon, I was afraid we'd never see another modular house with R40 SIP walls.  Luckily, it seems other companies are now starting to offer this. 

Be warned... I know nothing about the following companies.  I mean it, nothing.  I am not certain if they can or will build you a modular house with structural insulated panel walls.  I am listing them here now because I have been told they will.  Since Penn Lyon is out of business, I am hoping that someone will build a house like this for you.

I am told by a reader of this website that GoModular will build with SIPs: http://gomodular.com/green-modulars.php

I also had a brief email exchange with Paul at Avalon Building Systems.  He was the general contractor for our house.  He tells me he introduced the concept to KBS modular: http://www.kbs-homes.com.  He also tells me that Keiser will build withs SIPs as well: http://www.keisermaine.com/homes.

Honestly, I could not be more pleased that this is catching on.  I applaud the companies that are doing it (even if all thye are doing is riding the "Green Building" craze).

Ed