Most of the online schutzhund suppliers sell them, not sure if you want the total length of the leash to be 4 feet or just when it is on the clip, so here are some options. Dogsport gear has several options
I've heard good things about Dogsport stuff, but have never seen any of their products.
I really like my Ray Allen leads, namely the fact that they are very strong, do not stretch, and are extremely light weight. I also like the fact that they are sewn and riveted. Ray Allen's leads are really stiff when new, a healthy amount of conditioner got mine broken in nicely.
I don't care for For Dog Trainers leather work, its really thick which is nice, but very heavy. Its weight makes it harder to get feedback from and a bit less consistent on corrections (for me at least). FDT is also painfully slow at shipping from the times I've ordered from them.
I just got a harness from Hortons Quality K9 and I have yet to see leather I like as much as Hortons. The stitching is really nice, the old school copper rivets are a great touch too. The people over there are as nice as can be as too.
Thanks, everyone. I will check out all the links. Ideally, I'd like the total length to be 4 feet. I have a great belt that actually has a D ring on each side, so it's perfect for attaching a lead to go hands-free. Since it's a normal belt, it threads through my belt loops and stays in place really well. This is for Shanoa's reactive dog class, so I'd prefer to keep it to 4 feet at the longest. I'm also looking for fairly lightweight - she doesn't pull and she won't get corrections, it's just an easy way to attach her to me and keep my hands free.