Reduce browser header bars to focus attention, or counter-productive?

This is a general question about web design.  I'm reworking an asp.net application using VS2010 (tested on IE8 mostly) for doing real-time collaboration using drag and drop process diagrams with context menus  (so it has lots of detailed javascript routines).  

I'm down to tweaking usability and expanding browser compatibility.  The app has a "Main Page" where all the work is done.  Originally I designed it so that this page would open with javascript window.open, and have no menubars, toolbars, etc, at the top, and to be maximum size with no scrollbars and not resizable.  My thinking was that this was not a standard web page where the user would consume content, click on links, etc.   This was a single page where they would stay and do work, and so I wanted to maximize available space, remove distraction, and prevent size changes that would hide controls.  

I appreciate the guideline that if this were a regular web page the users would not like having restrictions on the use of the headers, etc.  But for a single purpose page, I still don't think the headers and such are going to be useful, and if people want to multi-task they can open another browser instance.

But now I'm trying to get it to work with Chrome and FireFox, which makes the "windows.open" command trickier, and maybe the user would need to adjust browser controls in some way to get the app to work the way I want it to, and thinking about whether it could be used on tablets so I might need scrollbars.

What I'm hoping for is any input that would help me think about the balance between 1) ease of development for multiple browsers, 2) the "stay focused" approach of no unneeded page header bars, 3) simplicity of not scrolling (which affects the drag and drop) and 4) general hassles of having a non-standard page (no scrollbars, headers, etc.).

Any links, thoughts or suggestions on this would be appreciated.

Thanks!