In the meantime, I thought I'd share with you a nice resource I happened upon the other day. Lori, a trained Montessori teacher who is now a full-time mom, has a website where she sells some quality printable materials. I especially like her offerings in botany, biology and zoology. For reasonable prices she will either email (PDFs) or print and send to you a wide range of 3-part reading classification cards. If you order the vertebrate nomenclature series (parts of a mammal, reptile, amphibian, bird, and fish) with each 3-part card set also comes a definition for each part. This can easily be used to make AMI-style definition stages. Just print off two extra sets of pictures.
In addition to her online store, Lori has a great blog on Montessori topics. Check it out when you have a chance!