I wrote this custom range slider for xamarin.android becuase the default seekbar\rangeslide provided didn't fit my needs and the double button range slider control in the Xamarin component store is very limited. This controls gives you the option of using 2 buttons on the same seekbar. It comes with 2 default images for the buttons but you can override those images with your own, if you chose. It also allows you to provide different scales for different scenarios.
There are a few bugs with this control but with a little effort you can figure out how to get through those. Its a good start to writing your own as well. I'll be fixing those bugs soon, if you have time to wait. Feel free to use as you'd like.
If you have any questions or need help, please feel free to contact me. I'll provide as much help as possible.