We have softwares like StylesXP and Windowblinds and more freewares that changes visual styles of windows operating system. Stylesxp is unique and it does visual style modification. Note visual styles differ from themes, if you want to have idea about this check styleXP's official site.
(I don't want skin windowblinds, i'm interested in changing visual styles of windows 7 and vista without any external application)
Is it possible to have visual style modification on Windows 7 and Vista? Any pointers for development of those visual styles ?