I've had good success doing psuedo 'sous vide' in just a little cooler.
I fill it with hot water from the tap and then add boiling water to get the temp up to just a couple of degrees above my desired temp.
Typically I use it for doing rib eyes and have left them in there for a couple of hours before. The temperature stays pretty darn stable over that period of time.
Pull them out, open the back, slap them on the infrared burner to crust them up and they are perfectly cooked all the way through.
Don't see why that wouldn't work for sausages.
That being said, I did by a little temp controller, a pump, and some heating elements that I plan on using to make a 'real' sous vide someday.
The controller I bought is the STC 1000 w/ sensor. I actually have one of these hooked up to my chest freezer and have it set to keep my beer cold.
Pretty darn in-expsensive on ebay http://www.ebay.com/itm/Digital-All-Purpose-PID-Temperature-Control-Controller-STC-1000-W-Sensor-110V-/370773791107?pt=LH_DefaultDomain_0&hash=item5653d71183