You really can't put a "cap" on the number of accommodations needed because it totally depends on the child's needs - you could have a child with multiple disabilities who needs multiple accommodations. You base the number on what is needed - not on whether or not it is difficult to implement. However, you make a very good point about a teacher's ability to implement multiple accommodations (25 is quite a large number). Without knowing all the facts it's difficult to say whether a collaborative classroom is best. I would start by pointing out the impossibility of a teacher to stay on top of all these accommodations and ask for push in minutes from a special education teacher or an aide for the classroom - both of which can assist with the accommodations. If that doesn't work, then a more restrictive environment might be an appropriate discussion.