I am pretty sure that the Speech therapist we had through early intervention (done as of last week) had limited experience with children like my son.
I'd say that that is a matter of course when dealing with gifted/autistic-- because most people who have autism also have cognitive delays, the gifted/autistic combination is rare, especially when you get to a kid whose giftedness is really out there.
At some point I looked at the statistics and concluded my DS's combination of gifts and deficits is somewhere between 1 in 25,000 kids and 1 in 50,000-- which means that none of his teachers or therapists will likely have encountered one like him in their career.
I will say that it *is* possible to find people to help; but as you note you may have to work hard to find the right people. We have found some people who were flexible in their approach from the beginning, and some who became flexible as they learned to understand DS. But yes, we have had to do a lot of explaining.
As for the 1/2 hour eval: not remotely appropriate. I would expect about 5-6 hours, including a complete ADOS, Conner's behavior checklist, and Vineland adaptive skills questionnaire. They didn't do their job; you can call them to find out why not, or you can seek an evaluator who will do the job correctly.
Hang in there,
DeeDee