The meaning of collaborative may differ from area to area.
Our district does team teaching. It's not referred to in the district as collaborative teaching to parents, but I believe that's what it is.
In 2nd - 4th grades, difficult child had a 2-teacher team. Beginning in the 5th grade, his teaching team has consisted of his four core teachers.
I'm sure they collaborate on different issues, but the one I most familiar with is my difficult child. lol
Example: difficult child has been having some problems in school lately; something (unknown) happened in January has triggered difficult child. He's been having difficulties ever since. I had been in contact with-all his teachers trying to identify the trigger and get him resettled. Last week the team leader called for a brainstorming session -- the team was going to have meeting to see if they pinpoint the trigger and do some problem solving.
I like the collaborative approach thus far. I think it's been helpful for my son in several ways.
In your situation, however, I would be leary of transferring my child to a school that indirectly is saying we don't really do individual education plans.
IDEA 2004 recognizes that there are gifted children with disabilities. While nothing surprises me about what a school district will tell a parent, I'd be very surprised to learn that a school district would put "you waive rights to the IEP and it becomes "consultive"." in writing. This would be a violation of IDEA, State law, SEA rules and regs, and most likely sd policy. Don't be shy about asking for written policy, rules or regs.