Yes, Lacy Hunt and Van Hoisington are talking their book. They have had clients in long-term Treasuries for years. But their strategy has produced rich rewards. They're out with their 4th-quarter commentary, which as usual is excellent. The whole thing is worth reading, but here are the money quotes:

In the world’s three most recent debt deflations – the U.S. from the 1870s to the 1890s, the U.S. from the 1920s to 1940s, and Japan from the 1980s to the very present – the low in long term interest rates occurred about 15 years after the end of the debt mania (Chart 5). Even 20 years after the end of the debt boom, interest rates were not much above their yearly average lows. Using this history as a guide, it would not be surprising to experience a decade of low and declining interest rates.

During 2008, long term Treasury bond yields fell from 4.5% to 2.7%, producing an extremely strong total return for such investments, as typified by the Wasatch-Hoisington Treasury Bond Fund (WHOSX), which returned 37.7%. Credit problems affected returns elsewhere in debt markets, limiting returns on the Barclays Capital U.S. Aggregate Bond Index (formerly the Lehman Index) to 5.2%. The decline in long Treasury yields reflected the intensification of recessionary forces as well as a collapse in inflationary expectations.

While the historical record indicates that the ultimate low in Treasury yields lies years away, the path to the ultimate low will be anything but smooth or linear as significant volatility continues. As the experience from U.S. and Japanese history indicates, many “false dawns” will occur, with investors assuming that the long-delayed cyclical recovery in economic activity is at hand. During these pleasant but relatively short interludes, stock prices will probably rise dramatically and bond yields will increase. If history is a guide, however, these episodes will further drain wealth and will be thwarted by the persistent forces of the debt deflation. With yields in the long Treasury market very low in nominal terms, the real return will be greater if deflation sets in. Moreover, in Japan from 1988 to the present, as well as in the U.S. from 1872 to 1892 and 1928 to 1948, the total return on Treasury bonds exceeded the total return on stocks. Such a condition cannot happen for the long run, but it did happen in these three instances spanning two decades. As a hedge against a recurrence of a prolonged debt deflation, some investors may want to consider even larger positions in high quality, long term Treasury securities.