* When walking in the halls, you could start out by having him/her extend his arms out in front of him and telling him/her to imagine a bubble all around him that is as big as his/her extended arms. He/she can't get any closer to another person that that. Once the line begins to move, require him to fold his arms or put his hands in his pockets while walking in line.
* Give him/her a permanent line leader job, so no one is ever in front of him (except perhaps you)
* This next one will work on more than one student at a time. Set up a token economy system where those who ARE following the classroom rules are randomly rewarded at regular intervals (and make a really big deal of it so everyone knows why that student is getting the reward). I'd suggest you begin by doing it every 15 minutes, then fading it to 30 minutes after a couple of weeks, then to 45 minutes, etc. You could make the rewards immediate, by giving the students something they can use right away, or you can give them tokens that they can accumulate and turn in for bigger rewards after they've earned a certain number.
* Have him/her demonstrate the class rules to the rest of the class a couple of times a week. Ask him/her to play act what it looks like to follow the rules. Not only will this legitimately give some of the attention he/she clearly wants, but it will highlight for you right away if part of the problem is that he/she just doesn't know what good behavior really is. It's possible that there AREN'T any behavior expectations or standards at home and they really need you to show them what those look like.
* BE SURE to praise and reward when he/she DOES follow the rules. In most cases, the praise and reward should be a major production. Have the whole class clap for him/her or do some other activity to note the success on a grand scale, but something quick so you can move on to what needs to get done.
* Have you tried playing classical music while they're doing their work? I know this isn't always possible, but at times when it could be done, it might make a difference.
* Turn off a few of the fluorescent lights if you can. Studies have shown that fluorescent lights increase negative behaviors.
* This one sounds a bit weird, but studies have also shown that behavior improves and academic performance rises when children can wiggle their toes. If you can tolerate the odor from their feet (and I know well how potent it can be), letting them just wear their socks in the classroom might help.