As many as 40 per cent face problems with courses or jobs, and Scottish Office ministers have made it clear that meeting their needs sits near the top of the "social inclusion" agenda.
The committee's thinking was revealed to The TES Scotland by Robert Beattie, its chairman, who is himself confined to a wheelchair. Mr Beattie has since been appointed to head the Scottish Further Education Funding Council, which will be charged with implementing many of his post-school proposals.
The remit of the committee was to consider the 16-24 age-group. But vulnerable young people start disappearing from the system as early as 14, the committee found. "We have taken a wider view," Mr Beattie said.
The committee has been convinced that much more widespread support is needed for special needs leavers. Strategies are to include the use of key workers, peer mentors and written "transition" profiles or assessments.
The 15-strong committee has been gathering evidence and digesting good practice since it was set up by the Scottish Office in April last year. It ranged widely, consulting on provision not just for young people affected by physical and mental disabilities but also those with social, emotional and behavioural problems.
Its report, due to be delivered to ministers by the end of June, will be one of the first major set of recommendations to be considered by the new Scottish executive. The committee found that four out of 10 young people with special needs faced difficulty entering education and employment in some parts of the country.
A survey of provision for special needs students in further education, commissioned by the committee, attracted responses from 40 out of 47 colleges but revealed a "patchy" picture.
The Government has already set a wider access agenda with a target of an extra 42,000 college and university places by 2002, particularly for people from previously under-represented groups, funded from a pot of pound;100 million.
Mr Beattie makes it clear that if targets are to be met and special needs students included, "colleges have to put in extra support structures beyond the norm for ordinary students".
The process would be "a learning exercise for colleges" and will take time.
Young people who displayed what Mr Beattie described as "chaotic behaviour" should be assigned a key worker, the committee's report will suggest. This would be "someone identified to work with them from perhaps as early an age as 14, and who would stay with them perhaps for the next five or 10 years".
Key workers would have to seek out the young people since they would already have "voted with their feet" and dropped out of the school system. They may be homeless, or substance abusers. One approach would be to use volunteer mentors or advocates - themselves young people.
"In the same way that we need to find the right provision for these young people, in education, training or in a work placement, we need to find the right way to find them," Mr Beattie said.
But he stressed that young people should be advised to go into further education only if it suits them. Alternatives could be voluntary work or training.
There is no straight line from school to further education to training placements for these young people, Mr Beattie said. A useful tool would therefore be a "transitions form", which would include personal details such as health and also a skills profile.
"Transitions are difficult for this group of young people. We are keen to develop progression rather than have them running on the spot which is what has traditionally happened to a lot of them," Mr Beattie said.
The committee is to encourage a variety of innovative projects involving colleges and employers across the country, inviting bids for multi-agency pilot projects. "What happens in Stornoway wouldn't be suitable for Easterhouse," Mr Beattie said.
Ministers will now consider whether, using the model of the Garrick report on higher education in Scotland, they should draw up an action plan in response to the Beattie report and publish both in the autumn.