@DocJoe: Well in Delphi you would just drop the TWebBrowser ActiveX control on your form. Then you create the form via a 3DGS plugin DLL and paint the form to your DirectX texture (panel or entity). I'm not sure if the user would be able to send clicks to the current web page (I would have to test it) but keyboard navigation is definately possible.

You can see an example of this here. This is someone elses site and uses GLScene (OpenGL) but the same thing is possible with 3DGS.