dkstar88 from PockHero.com created three different button components for Delphi Firemonkey derived from TSpeedButton. The TWeb2Button has the option of being able to change the background color of the button and it has a glassy effect. The TWeb2TabButton has the same properties of TWeb2Button but it allows you to set one side to be flat so that it can be used for tabs. The last component is called TWeb2ImageButton and it allows you to set images as the normal button state, a button down image, a button over image, and finally a button active image. The original components were created for Delphi XE4 but I upgraded them to work with Delphi XE5 by adding FMX.Graphics to the uses clause. These buttons should work on Android and IOS (in addition to Windows and OSX).
Update: I added a new line to each of the component definitions so that it will show up in the IDE for each platform:
[ComponentPlatformsAttribute( PidWin32 or PidiOSDevice or PidiOSSimulator OR PidAndroid OR pidWin64 OR pidOSX32)]