Room Management in Mainstreamed/Integrated Classrooms

'He needs so much time - what do I do with the other 30?' The question is not obstructive, not reactionary, not symptomatic of laziness and it revolves around a collection of seemingly insoluble problems.
Given that handicapped children need more individual attention to make progress; given that many need short regular doses of instruction; and given that the intellectually handicapped benefit from more prompting, more over learning and a generally more rewarding teaching situation, how best can ordinary classroom organisation be modified to accommodate these needs?