I vaguely recall taking apart a blank cassette (that was assembled with screws) and using those parts to repair a mangled tape. But I don't think it had the failure you describe.
The ANC-2 [link|http://www.studiosoundelectronics.com/cassette.htm|here] sounds like what you need.
Caveat emptor, etc., etc. It just showed up in a search.
HTH.
Cheers,
Scott.