Try on here
http://www.bing.com/search?q=652+3.5...&sk=&x=69&y=21
http://www.teamassociated.com/reedy/...s/accessories/
If you cant find any that suit I have reedy 652 connectors 6 male 10mm 6 female 8mm (as your measurements) connectors nip. Im not sure they still make them as I got 2 packets of them for a project a while back so I can spare one packet if you need them.