I have Stu's Double Jeopardy! I have both used it and created a board for it. Like you said, however, it doesn't have the option for two rounds, and it seems to install some crap somewhere in the WINDOWS folder, which makes it impossible to play from a flash drive on a protected computer. Otherwise, I give it my recommendation.
(I've also created a buzzer lockout system for possible use with Jeopardy!, but it's not very user friendly yet.)