Thanks for writing back and for providing details on this matter.
1. As my colleague said in the previous post, we are working on a System Theming Engine which should enable the standard Windows look-and-feel for most of our controls. This engine, however, is still in development process and we hope that we will finish it for our next major release.
2. System Theming mechanism would enable us to achieve much more consistent look of RadControls in comparison to the standard Visual Studio Toolbox controls. We have also the Vista theme which is designed to resemble the standard controls as much as possible. In general, we are constantly working on polishing our themes and improving the consistency of all themes that we ship in our suite. Last but not least, you can design your own themes and fine tune the appearance of our controls so that they match your requirements.
3. I am happy to inform you that we are working on a Theme Viewer application that is pretty much what you suggested: a showcase application that contains all of our controls and allows the user to change themes on the fly and see how they look.
I hope my answers are helpful.
However, you can write back anytime you have further questions or any suggestions.
the Telerik team