Lots of factors here - but on average 1 hour per 1000 is reasonable. I have played on three consecutive nights with my nearly all infiltrating 2000 point SM army (70 models).
First against Deathguard w/less than 50 models. He had demons to summon and was a very precise player - I am mostly shooty, but we got into HtH on turn 2. My commander held off the Great Unclean One for 5 turns and we took over 2.5 hours until the final attack phase when he killed my commander...finally. I had about 250 points left on table at that point, he had over 1000. Way too slow IMHO. He has played quite a while, as have I. It was a little too precise for a game he was winning easily.
Then I played a fairly new player 2000 points of SM v SM. He had no list ready and that alone took 35 minutes. From agreement to play until final round of HTH - 3.5 hours. I was pulling my hair out. Luckily he was one of my friends and I understand the learning process, but how many times do you have to remind a SM player that they need 3's to hit in shooting and 4's to hit in HtH versus other Marines.
Finally, I played my most regular opponent. He played Chaos, also a very heavy infiltrating force. 2000 points - 1 hour 20 minutes. This is how 40K should be played. Friendly banter between each other, but very little with the crowd watching. We know the rules, we know our armies and the play was fast. We trust each other to move without watching every move, we do HtH simultaneously and tell each other what saves to roll without having to watch. Fun game and then we played another. So nice.
In short, everyone should try super hard to have a list ready when they arrive for game night with adaptations in mind for larger or smaller games. Know what your stuff does and anticipate while setting up what dice rolls you will have to make. I would go crazy (well at least inside) at a tournament here there were only 2 turns played. Someone is doing something wrong, or so overanalyzing the game that it is no longer a game. Its just a game with metal and plastic models with dice and tape measures. Sure it takes time to set up 110 models of guard, but I do it all the time and we still get done in 2-2.5 hours. You just have to concentrate.
Now some here may argue the idea that the game is also about interaction with the opponent - I agree. There is a fine line between play and interaction. I love both and there has to be a common play speed that is acceptable to both players.
More comments would be great on these topics.
BTW - also played a day-long 6-turn game 12,000 points on the table - 4 players. We set up terrain the night before and then played all day with 2 food breaks. SO MUCH FUN - but it was a LONG day.