The documentation is inaccurate about the number of thumbs supported by the slider controls. It says:
The number of thumbs allowed on the slider. Possible values are 1 or 2. If set to 1, then the value property contains the current value of the slider. If set to 2, then the values property contains an array of values representing the value for each thumb.
The controls support more than two thumbs. (I'm pleased it's wrong.)
I wanted to simulate the Photoshop Blend If sliders. I needed four thumbs. The controls work just fine. I set thumbCount to 4 and the values array returns the position for four thumbs.
Based on the help file, I scoured the Web looking for a Flex component that supported four thumbs before I tried setting thumbCount = 4.
I hope this helps others and saves them a little time searching for an alternative. I haven't explored the limit by setting thumbCount to a ridiculous setting, but it works fine with thumbCount = 3, thumbCount = 4, etc.