My contribution to the wishing well is a board game based on the original (not #2) Dawn of War PC game. With all the Games workshop licenses FFG as been permited to use I cant imagine this one being to far out there... except for whatever license Relic holds.

More then anything, I want a board war game where I can play the Tau, and shoot at Necrons =P

That is cool. Do you envision lots of plastic with this game?

If you want Dawn of War-ish feeling, I suggest you to play Wh40k Tabletop. If you want massive armies battles, then go into their Apocalypse setting, which even includes Titans and such, not to mention you can still build and customize your army as you wish.

But as another boardgame, I don't know...

Miniature games are not board games. Board games do not generally require nearly the monetary or time investment. I for one would welcome such a game. It could possibly use a modified Battlelore system . . .