Vcl.Styles.Utils is a open source set of utilities that augment vcl styles. In fact some of this code has been added to Delphi itself.
It is troublesome that Embarcadero has not fully implemented vcl.styles by now so that more components are styled. This is the only way to style some components that I know of.
It is not perfect but they continually are improving it.
I know but i have old code i use that are not developed anymore and do not run on newer version.That's ok. I can live without the skins. It would be good if the imageen dialogs were forms so i could drop a component onto them for skinning :) Pierre
Old code can be updated as well. Its time to move up. Your could move up and gradually convert the old code as time permits while leaving your old version installed as well. Eventually you will have an app with a number of new features.
ImageEn v5.2.0 has just been released which supports VCL themes if you enable it in ie.inc. However, as you say XE2 or newer is needed for theme support.
The open/save dialogs are standard Windows dialogs, so cannot be altered, however the print dialogs are all forms, and you can modify them in your source folder (just remember to remove the defines so you can view the form in the IDE).