Gradients on buttons?

[Keith Clarke]

Hi folks,
Is there any particular reason why buttons don't support gradients - at least for those styles of button that are not attempting to be (desktop) OS-compliant, such as rounded rectangles?

This seems strange as native gradient support for rounded rectangle buttons would (seem to) simplify web and mobile app development(?)

The current (manual) workflow a tad long-winded: 
  for each button
      for each state
          create rounded rectangle graphics for fill and border, group, import as an image and set as the button's icon
     next state
  next button

Am I missing a trick here - or is it perhaps that with behaviours, buttons are now obsolescent for the UI and instead, we should be setting common, button-like behaviours and styles onto graphics (or groups)? 

But currently, behaviours have to point to buttons - and buttons don't support gradients - return to line 1!!

Can anyone help break this loop?
Best,
Keith..