I can't seem to find any GUI framework's for as3 that are as good as any the applications I already see out on the web; Is this something most people code themselves or am I missing something in flash itself?

I'm looking for dialogs/windows, buttons, text boxes, combos, drop downs, menus, etc etc and the ability to extend the components to make new ones.

I'd also prefer it to be as3 but any others will do also.

May need to elaborate a little.. I'm actually looking for a framework to allow me to create my own GUIs in flash, custom skins, colors, styles, etc.