Hopefully you’ve all heard of Charlotte’s Tandems by now.
http://www.charlottestandems.co.uk/
http://www.facebook.com/groups/139839216034492
In their own words, “We lend, at no cost (i.e. for free), tandems and tag-alongs to (and only to) people with disabilities or additional needs, who are unable to ride a bike safely on their own, so that they can enjoy the wonders of cycling“
One thing they don’t do, is find captains for disabled stokers, it’s up to the disabled person to find their own partner.

However, there is now a new group to help with this.
http://pilots-stokers.weebly.com/
http://www.facebook.com/groups/1656859641194681
Their aim is to put able bodied experienced tandem riders or owners in touch with disabled cyclists.

It’s a new group and not many people have signed up yet, although one of those who has is a ten times German track sprint champion offering to pilot people on the Manchester Veloldrome. 🙂
If you’ve got a tandem of your own, or could captain one of Charlotte’s Tandems, please get in touch with them.