Well, I have learned so much in the last few months about Core 3 / Smart Graphics. In order to create your own custom look for a slider, you will need to do a few things.

You would need to create the indicator graphics and the "track" that is moves on individually as separate graphics. That part is easy enough. To get then into VTPro-e, you would have to edit the theme you are currently using (let's say CT-Neo) to add them in, so they would be available in the drop down menus for the indicator / button style and track style.

Before that is possible, you would need to create an image map for each one, and a style for each one in Studio. You would also need to add those styles to the correct controls styles in properties. Finally, you would have to check off those new graphics (whatever you named them) in the Controls Styles attributes for each category.

So, you have to jump through hoops of fire to create your own sliders, but yes it can be done, and I have done things like make the media player smart object look any way I like. If you are a graphics guy and have some patience, it can be done fairly easily, but it took me months to get to this point.

Custom floorplans with individual zone / room buttons (in the exact shape of the room) that light up with feedback when something is on etc...