If you haven't heard of SkinCrafter, here is the website: http://www.skincrafter.com/.
It supports majority of the Windows programming languages such as .NET based applications, MS Visual C++, MS Visual Basic, Borland Delphi. (See Here)
If I know it correctly, externals in RunRev for Windows are coded using VIsual C++ so if anybody is skilled enough, you can create the SkinCrafter external Windows RunRev. It would really be a big help to programmers who are now bored with the same Windows' controls and are too busy coding to create skins which by the way is tedious to implement. Also SkinCrafter comes with some set of skins ready to be used on your program w/c are also submitted by other SkinCrafter users.
Please don't take this for granted...
