SHAMELESS PLUG:
You will be able to use ANY monitor you like with your A4000 by using an internal scan doubler and flicker fixer. I just happen to be selling one on ebay UK at the moment (with worldwide shipping):
A1200/A4000 Scan Doubler & Flicker FixerIt clips onto the AGA chips in the A4000/A1200 and allows all Amiga screen modes to be displayed on any PC monitor, via a standard VGA connector on the end of a cable.
Steve.