That does work well for sous vide. Check out my post about cooking a chuck steak at 131 for 4 days!
http://smokinitforums.com/index.php?topic=4390.msg39848#msg39848You can break down a tough cut of meat at a lower temperature given A LOT of time. You end up with a very tender, prime-rib-like medium rare steak. 130 is actually a safe temp if held for 112 minutes or more (not widely publicized since it mostly pertains to sous-vide and requires precision/accuracy. 140 is safe when held for 12 minutes or more).
I also started wondering about lower temp prolonged smoking/cooking. Sous vide is in a sealed pouch. My fear with super low and slow in the smoker, is even if you can get the meat up to a safe temp within 4 hours (which is possible, start at higher temp, turn down when IT 140 is reached), a prolonged period at a low temp might eventually just dry out the meat. You'd need to wrap it, or cook it in a pan with liquid (braising). As long as you keep the IT of the meat above 140, anything is possible I suppose. You could always try it and see what happens. As long as you make sure it stays at a safe temperature, the worst that can happen is that it turns out terrible.