Yes, thanks, Thaddy, I edited my question to be more clear (by Qt I ment QtCreator, and not the qt-ws used in Lazarus).
It was a question to you, but I will appreciate any info from the other community members too to the other parts of my question.
I found that there is a project in Lazarus CCR, doing an InterfaceBuilder for Lazarus, which will be like the XCode InterfaceBuilder and the GUI could be used in both Lazarus and XCode... Delphi/ Lazarus are not just cross-platform, but also cross-technology and this is even more powerful, and in this in mind I am asking for information about interoperability between Lazarus and QtCreator as IDEs and Application Projects?
Thank you!