Thanks so much for all the responses. DH and I read through all of them together tonight, along with some information a neighbor sent us last night, and have decided we're going to pursue outside testing. I don't believe school testing will show much based on talking with our neighbor (whose DD7 is at the same school and was recently diagnosed with dyslexia). She gave us this fact sheet, which we found really helpful.
http://www.interdys.org/ewebeditpro5/upload/TestingandEvaluation.pdf It corroborated my thoughts that, although DS is a proficient reader for his grade level, the substantial gap between his written language abilities and his other abilities is a strong indicator that a dyslexia evaluation is worthwhile. DS doesn't have the fine motor skills issues or spatial issues that many posters mentioned, but we see a lot of the issues discussed in the fact sheet on phonological processing, fluency, and reading comprehension.
It's so helpful to hear others' experiences. Some of it fits DS, some of it doesn't, which explains why this can be so difficult to identify; there's no single set of issues that a parent or teacher can point to and say "that indicates dyslexia." One poster noted to watch how DS reads when he's tired, because the giftedness doesn't mask the underlying problems as much. DS can't read when he's tired; he can't make it through a sentence without assistance.
Thanks to all of you; your experiences are helping us decide how to move forward, and remind me that I should listen to my instincts rather than doubt them.
Knute974, we're in the same area. FWIW, I'll PM you with testing info from my neighbor - they got some very definitive answers, although their DD may have a completely different situation than yours, and it sounds like you're probably done with testing after two goes at it.
