I think you overlooked some things. There's a File>Page Setup for some basic settings.
There's a File>Print Preview in IE5.5 and IE6.0. The Prin Preview screen in IE6.0 has a selection box for 'whole screen' or 'only current frame', which works on the screen. When I select Print ... from that screen, I get (in 5.5 at least, I didn't check in 6.0) radio boxes for 'As laid out on the screen', 'Only the selected frame' or 'All frames individually'.

IE offers what you want for print preview and printing frames. That's 2/3 of your wishes.

IE doesn't offer a 'fit to page' as does MS Excel. I'm sure the makers of Firefox would welcome your Firefox-entension to do so, but I'm afraid it's rather difficult to program, especially as it should work on Linux also. It should be tightly integrated with the html-machine of the browser.

Kees