Marty's Sliders
Marty's Sliders contains both horizontal and vertical slider controls, that utilize graphics, so they'll look the same cross-platform. If you use transparent PNGs they will work well with a background image or color. I've included a few examples. There's an option to show the value of the slider as well. These sliders can count from either direction and can accomodate negative numbers.
2014-05-09 I updated the stack due to the use of a variable named "scaleFactor" which is now a reserved word.