A few thoughts...
For lighting up a room evenly, consider a beamspreader, to remove the hotspot in the beam, and brighten the edges. Want to look more 'executive', then the Surefire executive series is available in black. As for runtime, bring more batteries, or a spare light.
If you're going to be using it for hours per day, every working day, consider a rechargeable. I have a Surefire 8AX, it runs for 50 mins, puts out 110 lumens, you can get beamspreaders for it, and I have enough Ni-Cd batteries for around 4 hours light (and the chargers come with both mains AND 12 volt car plugs, so you can charge a battery on the move).
Good luck in your search for light !!
:touche: