I've read in several threads that achieving higher levels of DO is mostly about increasing the surface area of the water that comes in contact with the air. That's why small bubbles in a bubbler setup are better than larger bubbles. There's more surface area exposed to air if the same volume of air is made into smaller bubbles.
So my thinking was to just reverse the method of getting that large volume of surface area. Instead of trying to make tiny bubbles, you make tiny water drops that then contact more air in the "spray chamber" and then fall back to the res. Like I said... it may be far fetched, but it's been something I've been thinking about.
I might give it a shot with a vegetable grow first to see if it works. If not, I'll likely introduce a homemade venturi. I'd rather run water than air because I can use the inline water pump for res changes as well. A couple ball valves and some T's and I don't have to move the plants or the res at all, which would be a nice change from what I've done in the past.
@petflora, I was wondering when you were going to show up telling me to check out your thread