Is it possible to remove all "chrome" from a browser window, without going full-screen (with or without CSS/js) Ala Quicktime modal?
So all you see is the content and the drop shadows no toolbars, not even the close/minimise/minimise toolbar.
No, it isn't.
You can open a new window with some chrome removed using the strWindowFeatures features of open, but you've never been able to remove the title bar and more features set to Always On by browsers as an anti-phishing measure.
You could get something similar to what you are asking for by just using an iframe in an existing page. Obviously, it won't be free floating.