Is this ITBS?
Is it content-specific testing? If so, it's possible that she's testing low because she has simply never been taught those things.
Secondly, in terms of the explanation you've given above, is that problem (physical, motor-skills vs. cognition asynchrony?) likely to impact her ability to learn after a single gradeskip? Would it be accommodated in a classroom? Probably, is my guess, but the details matter a lot there. Is she still within the normal distribution for conventionally-aged peers in the next grade up? Again, probably, but it matters how it would be handled, and how the teacher(s) would communicate their assessment of that issue.
Where I see problems in your test scores (having a kid with a 2y skip at this age) is exactly where most kids have them--
writing fluency (speed, most likely) and some computational speed/automaticity issues with math.
There is that one subscore on the WPPSI, though... "picture concepts." I'm not entirely sure what that one indicates, but maybe someone else will know. It's possible that it merely indicated that your child had been so accustomed to thinking symbolically that she hasn't developed that area in a fully age-expected manner. I don't know, but I do recall that this kind of thing was problematic for DD at times when she was younger... it was also true, though, that her normal development in some very specific areas led to some weird blind spots occasionally-- like she could understand variable substitution and manipulation, but not sequencing simple series when she was ~4yo.
The rest of it doesn't seem a good reason to keep a child learning at a pace which is too slow, over material that has already been learned.
The problem that I see is that your DD's scores indicate that she would (probably) still not be getting instruction at an appropriate RATE for at least three or four years, even if you did skip.
It's also clear that any classroom teacher in your district is likely to identify her asynchronous areas as "areas to remediate" and force that issue. This does two things: a) it teaches such children that they must be perfect, and b) it teaches them that formal education is entirely punitive.
Is she unhappy with the current placement?
Have you looked at the Iowa Acceleration Scales? (I would.)
What are the best and worst case scenarios associated with skipping? With not skipping?
Can you "undo" the skip if it doesn't work?
Can you compact the next two years rather than doing a conventional skip? Does your district have split grade-level classrooms? That's one of my personal favorite options, because then your child CAN actually progress at an appropriate pace, and also stay with peers, and it softens the transition to the skipped grade the following year.
