Texas/Oklahoma area seems to have a high concentration, as does Montana/Wyoming (if anything involving people in that area can be considered high concentration) and Washington/Oregon. You'll find other makers everywhere though, so I'd look at all the other factors as more important.
Right now the best value for your money in the Mountain West is Idaho (been thinking about moving there myself). The best value for your money in the country though is Texas, without a doubt. Great employment scene, above average wages in a lot of industries, low taxes and, maybe most importantly low real estate costs. Houston is the cheapest major city in the country. The downside is that its hot, but on the other hand it never gets very cold. Folks are friendly (or they were before the invasions from Louisana (after Katrina), Michigan (after the 2008 crash), and California (after decades of stupidly high real estate costs there)) and the government largely stays out of your business.