The Judge's leather jacket is standard 'cafe' style leather motorcycle jacket , but it was custom made by Costume Designer Michael O'Connor and the costume crew of Rob Allsop (Key Principal Costumer for the Dredd movie). "Master" jackets were made and then duplicates of those masters were made for the background and stunt costumes.
While speaking at a discussion panel at the 2013 DragonCon Convention, Rob stated that it was a personal goal of the costume department to "create" as much of the Judge Costume as they could from scratch (i.e. not buying found items off retail store shelves). He said they were very keen on making the Cosplay/Costuming community "work" for their replica Judge Costumes. This philosophy is extremely evident with the level of detail put into the Judge Jacket.
Accordion leather adorns the sides of the jacket allowing for a custom fit and better movement for the wearer.
There are leather panels added to the shoulder/tricep areas of the jacket. The Right Shoulder Panel has a embossed eagle on it...
... and the Left Shoulder Panel, of Dredd's jacket atleast, has an embossed Judge badge with the word DREDD on it.
The cuffs of the jacket have zippers that taper the cuff to the wrist so that the cuff rests comfortably under the glove gauntlets.
Cast Urethane Elbow armor was secured in place to the jacket. The green color is lightly brushed on and allows the black of the urethane to show through. We matched Pantone #334 for a close green color.
The jacket also has a zipper sewn to the inside of the lower back area , which connects the jacket to the pants. This is a standard design seen in motorcycle gear and helps protects the wearer during accidents and , for the movie, helps keep the costume looking 'together' at all times. Rob Allsopp revealed this bit at his 2013 DragonCon panel.
Currrently there only one leather maker offering accurate-style leather DREDD jackets to the fans. LeatherNext.com, they are very fast with delivery and offer a good quality product.
FYI - if you are on ebay, and run across a Reel Images Leatherwear jacket, pants or vest that will suit your needs, that is a good buy. RIL developed the first accurate suit for the fans, but they had to close shop due to manufacturing delays.
For buying an ultra-affordable costume Jared Olive recommends, "... go with pleather. There's already a few judges going this route and have awesome suits. I bought a pleather jacket for about 30$ usd ... you can do a judge suit for 250$ (if you go one of the non-screen-used helmets.)"
When buying a Jacket, the main thing you want to look for is the pop-up collar with a single button snapand a metal zipper. The collar and Zipper is what people will notice the most.