The other contributor to mouth feel is the alcohol content. Being as alcohol is essentially bone dry, it can trick the tongue a bit. High alcohol beers are generally associated with sweetness, because they require a very strong first running wort, rather than a low grav beer which would use a lot more water in the mash and sparge.
So you're right in what you've said. To create a 'non-alcoholic' beer (there's never truly a zero percent beer, but by law anything under 1.5% (might be different in the states) is considered NA) you have to use either a shit load more water on sparge, or a lot less grain in the bill.
What we are looking at to create the low alcohol is getting an original gravity that will put our final alcohol by volume figure in the range of under 1.5% (I'm aiming for under 2%). This side of it is fairly easy to work out, a lot harder to actually achieve on my brewhouse.
Working on the basis that I want a 2% beer, I need to achieve a starting gravity of just 1.015 - which is where I normally FINISH ferment.
I think my biggest thing here will be yeast. At 1.015 there's not a hell of a lot of ferment-able sugars in the wort, so it's possible the yeast will just give up straight away... but before it does, it will get stressed and start converting some other nasties in order to live. So I need to find a yeast robust enough to handle this, and probably also Oxygenation will be necessary on transfer to start the ferment.
Clear as mud? Yes. I am still researching though!