This is not exactly what you are asking for but I'll note them none-the-less as they are free and accessible...

In my signature are four sets of play-along material that you can use with your computer.  It's mostly duets in student/teacher form.  You can play along with one line to practice your unison intonation or play your line while the computer plays the other line to practice your interval intonation. And it's practice in playing in steady time either way.