I have yet to do my first all grain, but I am READY to go in terms of equipment...just need the room to do it (I am in an apartment right now).
I was going to go with a manifold, but being as I am a lazy sod, I went with a false bottom deal. I got a 10 and a 5 gallon orange cooler and added the ball valves for em and to it all set up. I may go with a manifold one of these days, just to see how they work, but am going to go with this system first.
I have been doing grain steeping for 30-40 minutes in 155 degree water then adding to more water and extract, so it is sort of the same concept, however if you are going to be putting 9-15 lbs of grain in you MLT, you will have to have SOMETHING other than a steeping bag...and a very large one at that.