Did anybody tried to bind greater daemon into voidship? If yes, what was your ruling about it? what benefits, drawbacks?

Honestly, I would not consider it possible to bind a demon to a whole voidship. Maybe to a special part of the ship (like a Khornate Demon in the prow, so it eagerly turns to ram the enemy) or a Slaaneshi demon in the air filters that turns the crew into happy slaves with it's smells. But I doubt that a ship with a demon that fills out the whole ship could hold back from devouring, sickening, madden or however else incapacitate the whole crew and just end up as a space hulk until the demon breaks free and goes back tot he warp.

And yes, it might work without a crew, but demons usually don't like being bound to material things. So I doubt that the demon would be very happy.

Just my thoughts

There is mention of such a thing in the 40k fluff, but that was a chaos chip completly taken over by the deamon's bulk: think the outhershell of a spaceship with all the decks and most interior scooped out and one enormous daemon manualy firing the guns.

Suffice to say, there was no room for mortal crew.

Or, if you absolutly want it: Think Event Horizon.

Check out the 'Eye of the Abyss' entry in the Dark Heresy 1 supplement Creatures Anathema - it's a daemonic voidship that shoots possessed torpedos!

EDIT: I see from the like-titled post in the RT Forums that you already know this...