Let me start by saying I only read the First post of this thread, so this may have already been said, but here I go. I also have a leash reactive dog, he lunges and barks at dogs whenenver one comes into sight.
Over the last 10 or so months we have been working on it and actually seeing some results. We consulted a behaviourist, read a bunch of forums like this one, and read a couple of books. So here's the condensed version of what I've learned.
Baby steps, if your dog's threshold is 20 feet, work with him at that distance from a distraction until it no longer is a distraction, then try 15 feet, if it doesn't work, go back to 20 then try 18 and so on. The point is DON'T rush it. Think of it this way, the slower the progress the more solid it will be.
Watch me, it sounds to me like you have already done a lot of work in this field. Getting your dog's attention, specially when he/she is reactive is WAY harder than anyone will tell you, just keep working on it. If treats work for you, trust me, you're lucky, at one point my dog would ignore a rib eye steak if there was another dog around. I had to work on it for a while before i could get him to eat a stupid treat when there was a distraction around.
Don't yell, don't say no, don't give him a command unless you're possitive he'll comply, don't wrestle, just manage while he's throwing a fit. The INSTANT he calms down praise/treat/show him you're pleased, sometimes they will only calm down for an instant to catch their breath, you have to be FAST.
There's two GREAT books about his, Click to calm and Scaredy Dog. The therapy plan the behaviourist outlined for us is a combination of those two books and some other sutff of her own, please feel free to email me if you want more details (there's a lot).
Whatever you do, do not try to correct the lunging/barking/annoying behaviour, it'll only backfire (boy would I know). This sort of problem is best erradicated by teaching the dog to do something conflicting with the bahaviour instead of teaching then NOT to do it.