It is easy and very cheap to use lightbulbs and a $8 hot water tank heater thermostat to make a rooting cabinet.  The accuracy is +/- 1 degree and fully adjustable to what temperature you want to hold.    

I use bottom heat using heat mats. They stay about 10 degrees warmer than the ambient  temperatures. I get about 90% take.

After years of dreaming and planning, I finally built a greenhouse last winter.  I also created a mist table.  It mists for about 5 seconds every 5 minutes.  Cuttings are in a bed of perlite with a heat cable keeping the perlite warm.  My cutting success is over 90% like this and the cuttings grow FAST!  Bottom heat is just one of the factors here but I believe it to be a significant one.

Kyle