I'd look at a grade skip definitely and maybe consider the DYS application with a portfolio. My dd13 was quite disorganized at that age as well, but we didn't find that the organization requirements were such that she really needed to step up to the plate until 6th or 7th grade. Your dd has time to develop organization even with a grade skip before it will be more critical.
My dd skipped 5th and had a few struggles with organization her first year in middle school (6th) but not so much so that she wasn't able to maintain her grades. The work still wasn't superbly hard. I'd expect that your dd will still find the work not particularly hard either.
