Is sending a CV with recommendation letter a good idea? My coworker requested me to write a recommendation letter for an academic position  (postdoc). I myself am a postdoc, and afraid that my name may not be known well enough.

In order to support my credentials, I was thinking of either including a short bio or attaching a full CV with my recommendation letter. Is this a bad idea?
It's a little unusual. Typically you insert relevant material into the letter. Something like


  Dear So and So,
      I'm awesome in these 10 different ways
  
  Now let me tell you about Candidate.