You might consider looking at some Schutzhund websites, they have equipment like you're describing. Unfortunately, schutzhund equipment is all the rage and rather expensive.
As far as leashes go, I like the old fashioned kind with no stitching, the loop and the collar snap are secured with heavy leatherwork that looks like pull-through braiding. The clip is rather short, not a scissor type, and the braiding is supple and doesn't make a stiff section of the lead that would hang down awkwardly, like most stitched leashes. The added advantage is that this sort of leash just never appears to break at the snap or loop.
Myself, I think the problem might possibly be, not in the leash, but the collar(unless the leash is one of those stitched ones). I also think any collar that doesn't have a complete release to it, makes it much more difficult to teach the dog to heel correctly. While an exhuberant strong young dog with a powerful chest and neck is always something of a challenge to teach to heel anyway, I think the best way is to have a collar with a complete release. Rather than trying to hold the dog at one's side with a continuous (or even intermittent) pressure on the leash, the collar is usually loose, and the dog is guided into position by quick jerks on an otherwise loose lead.
The training collar should be rather snug, and fitted so that it is not resting around the base of the neck, but somewhat higher (not so high as behind the ears which would be uncomfortable), and the chain end when the training collar is properly fitted would not hang down at all - the properly fitted training collar would keep the snap from hanging down and being a problem.
The chain collar should have large (for your dog) smooth links that go through the large rings very smoothly. Any rust or rough spots makes the collar not work properly. Many cheap collars have large, poorly shaped links that don't 'run' through the rings of the collar at all well. Links that 'run' well fit smoothly together, a little bit like the links on an old english curb chain of a bridle.
The training collar is put on so the 'dead' ring (the one the leash is not on) constantly pulls the collar out to its widest - this one is on backwards, and is about six inches too long, both being very common mistakes. With a long chain collar left on the dog when not training, a dog can catch it on things and can injure itself very severely, but a longer chain collar also is far harsher on the dog and doesn't provide a quick, clean release. here's the incorrect setup -
http://www.google.com/imgres?imgurl...3&ndsp=10&ved=1t:429,r:1,s:14&biw=908&bih=363
To make it easier to put on, some use a 'martingale collar', which has one central ring where one clips on the leash.
http://www.google.com/imgres?imgurl...4&ndsp=10&ved=1t:429,r:2,s:24&biw=908&bih=363
I don't find they have quite as nice or as quick a release as a traditional collar, I don't find them as effective, but I use them on dogs with a thick ruff or roll on their neck. They should be fitted so that they sit on the neck in the right position - not right behind the ears, just a little further down...not near the base of the neck. Products that sit near the base of the neck or on the chest, just encourage the dog to pull, and can lead to confusion if you want to teach the dog tracking (I think you mentioned that).
Then the dog is corrected per position with quick snap - and - release motion, and 99% of the time, the snap on the lead is hanging down. But it hangs down so little that it's relatively out of the way. The trick really is in how the collar is put on and how it's fitted to the neck...as well as mastering the quick snap. The size would be two inches longer than the snug measurement around the neck where the collar should sit.
Some people then start out with 'directed heeling' on a long lead, letting the dog wander around to the end of the leash - I find that to be a horrendous waste of time as well as creating a whole set of behaviors the dog may never completely 'unlearn'. BUT...some people prefer that strongly.
I was going to post a youtube video of someone teaching heel...but after looking there for quite some time, I couldn't find even one that did not look like a total disaster. I found it a little disturbing to see so many 'trainers' training with incorrectly put on and fitted collars, but none of them were getting good results, either.
I was brought up using a very yanky-spanky Koehler type method of training, but 'got religion' on using treats and a much lighter approach when I saw how fantastic the results are - look at that wag and smile, as well as the reaction when the dog nearby barks like a banshee - the dog doesn't even turn its head - it's hard to tell from the camera angle, some of the finishes might be a little sloppy, but the overall attitude of the dog shows how effective the slightly lighter training style is.
