If you don't think that multiple grade skips would work or be something to which your dh would agree, how about a combo of a grade skip and subject acceleration if you can get the school to agree. We've had pretty good luck with that route for my oldest.
Also, you mention him currently working at 2nd-5th grade level depending on the subject. Which subjects are his strongest/what falls at 5th and what are you using for that assessment?
We've generally found that accelerated readers who are reading up to a few grades above level can be reasonably well accommodated within their classroom by mid elementary b/c there are usually a handful or more of kids who are a few years ahead in reading comprehension and able to analyze books in more depth. Advanced writers are less likely to be given appropriate (or any) instruction and kids who are many years ahead in math usually need, at a minimum, significant subject acceleration. For kids who are far ahead in math, if all other subjects are also at least a few years ahead, I'd go with a full grade skip and further subject acceleration in math if possible.
