Eitan,
You've come to the right forum for SDK answers :-)
SDK 5.5 doesn't include Flex components either. The purpose of our SDK is to provide the best extensibility to let plugins integrate with the Web Client but this is not a UI components framework. Our internal custom components are not in a state where we can share them publicly because upward compatibility would not be guaranteed.
Feel free to use the rich set of standard Flex framework components or build your own custom components to use inside your views.