If you get the (much cheaper) unwired Ranco, it's very easy to buy an inexpensive orange extension cord and wire it yourself. I consider myself to not be very handy at all, and I managed to do it just fine (I also brew beer, and precise temp control is pretty important there, too). Just be sure to use a decent extension cord for the wiring, and not one of the cheap white ones you might use around the house.

Here's a link to the instructions I used, very simple.

http://www.brewboard.com/index.php?showtopic=40898