Ideas
I have a self-contained GT classroom with 4th and 5th graders that are all identified TAG. I probably had 15 kids that fit your description at the beginning of the year. I remember feeling in August the frustration of feeling like some of the kids were their own worst enemies. I often had to apoligize to staff members for their outbursts, antagonism, and absentmindedness at the beginning of the year.
Just yesterday though, seven months later, I was thinking about how far they had all come when I put them in new table groups and they were working together to come up with flages, team names, and anthems. Instead of the beginning of the year fights, squabbles, power struggles, and non-starters, I walked around and thought about how much they had improved. Yes, there are still occassional outbursts or questioning of authority but I am starting to get a clear vision of the well-adjusted adult leaders that they can become.
The reason that I am sharing this is to let you know that there is a light at the end of the tunnel. I know it may be easier said than done, but I ask you to keep in mind your long-term goals for this student. Don't we all know adults that are highly gifted but have no social skills- they can't work in groups, they are very black-white, and they are completely disorganized in all areas of their life? As teachers, we have the unique opportunity to help shape these students' social skills now for their adulthood.
You asked for suggestions so here goes . . .
* Try to provide open ended choices for activities whenever possible. For my reading program and thematic projects, I use contracts for almost everything. I usually give the kids 10 choices for activities and include one blank line for a student suggestion that has to be approved by me. This eliminates many debates and justifications before they can happen because the kids feel like they get to pick their activity but it is something that you want them to do anyway.
* Use as individualized a curriculum as you can with constant assessment, especially in math, and let the student know it. (TAI and Accelerated Math are good examples.) If you can show them that they are needing to work on a skill because it is the narrowed in area that they have not yet shown mastery, then they can't debate with you. They have to either work through the work that you give them, or kick it up a notch to get to something that excites them more.
* Make and use as many grids, rubrics, and charts as possible to help superimpose organization on them until they actually begin to internalize it. In my class, the kids actually tease me about all of my excel creations. In addition to the contracts, the kids also have to complete a daily planner each afternoon that they return to school the next day, fill out a self assessment for many activities, and record each math assignment they complete. Yes, the kids who struggle with organization either fight these at first or have a struggling time keeping up with them, but I don't make it optional and I think about the longterm goals instead of getting upset with a day's mistake or a lost paper.
I hope that this was helpful and not preachy. I completely understand where you are coming from but as someone who teaches a whole class of TAG kids and who got her Master's degree in TAG, I feel really strongly about this subject. You obviously want to figure out something that works, or you wouldn't have posted. I know it can be challenging, but many of the very things that make the students gifted are the things that can feel oppositional or challenging. But in the long run, the effort is all worth it.