Currently all widths and heights that are related to the Slider and its elements are defined in the kendo.common.css file. Some other styles, such as margins and positioning, also depend on the mentioned sizes. Changing all these via configuration properties would be a complex and cumbersome task even for you as a developer. That's why currently we don't plan to introduce such a capability. In order to apply custom dimensions to the Slider, it is recommended to do one of the following:
1) append a custom CSS class to the Slider wrapper and use it to override the styles in the kendo.common.css file.
2) create a custom kendo.common.css file with the desired sizes in it
On a side note, the Slider's side buttons should be easier to use even by people with larger fingers.
the Telerik team
Join us on our journey to create the world's most complete HTML 5 UI Framework - download Kendo UI