The only person I know who has cut Colorado blue spruce for guitars is Don Musser. Stew Mac offered blue spruce guitar tops for a short period. It is very similar to Engelmann, and Bruce Harvie has said in the past that blue spruce has often been cut and marketed as Engelmann. It has a much smaller range than Engelmann, but is widely planted in yards. Just like red spruce, the name comes from the outward appearance of the tree, not the wood itself.
Here is a seller on Ebay who is cutting blue spruce for archtop instruments:
http://stores.ebay.com/Simeon-Chambe...QQftidZ2QQtZkm