Our DS appears to have dysgraphia, or at least he shows most of the symptoms of it. In addition he also is dealing with a growing inability to focus. I don't know if it is ADD lite, boredom, or something else. We got the opportunity to observe him last night at a meeting hosted by a nearby middle school with a crazy awesome focus on science (DS is WILD about science), and even when he was the most focused, he could not sit still. He was rubbing his face, his head, sliding down in his seat, sliding up. When I put my arm around him to steady him some, he started putting my hand on the top of his head, and holding it there. Things like that. We know what he is like at home, and just always assumed he was "that" way. Seeing him next to his peers in that context was illuminating.
FWIW, the above description sounds exactly like my oldest dd appeared in 2nd grade - before we found out she had vision challenges, so just something else to consider. Our dd has 20/20 eyesight, but also had double vision which caused the vision in one eye to shut down, lack of peripheral vision, and her eyes didn't track each other. We never realized *any* of this until she went through a neurospcyh eval due to challenges in school, and because her ped was convinced she had ADHD (she doesn't). Her handwriting was also very similar, at that time, to our ds' (who does have dysgraphia) but improved dramatically after vision therapy.
Re schools, we chose not to send our ds to our district's highly gifted magnet school for the very reasons you're struggling with your school - we heard feedback from other families in the program that the school equated "high intellectual ability" with "let's pile on lots of extra homework!". For elementary we chose an optional school that was open to all abilities but in theory let children have the chance to work at their ability level (didn't work out that way!), for middle school we chose a private school that isn't specifically for gifted students but has a high expectation of challenging academics, differentiates curriculum in math and languages, and has a student body that has a student body that has a much higher proportion of middle-highly gifted kids than our public school options did (with of course, the exception of the highly gifted program which pushes the homework envelope!). Neither of the schools our ds has attended had a high homework load, even the private highly challenging academic school - they challenge the kids to think, not to slave over books for hours at night.
It's probably just me, but for our ds I have never really felt grade acceleration was a good option, even though he is capable of working several grade levels ahead. Doing a 1-2 grade level acceleration would give him slightly more challenging work but still have him in a classroom where the students weren't intellectual peers.... plus it's helped our ds to be with age-level peers when it comes to social and organizational/maturity issues, he's just more comfortable and fits in better. To give him true intellectual challenges, he needs college-level courses at this point, so we supplement with online courses and intellectual experiences wherever we can "collect" them, plus let him have a lot of free time just to think, create, imagine, etc.
One other thought - if your ds has dysgraphia, that could be causing the homework time to stretch out - my ds has fine motor dysgraphia, and even with keyboarding etc he still goes through homework at a relatively slow rate - that's just his speed. He'd never survive in a school that expected 2+ hours of homework a night out of typical students who didn't have dysgraphia.
Best wishes - school choices can be so tough!
polarbear