Ok, I'm guessing one of these should do the job:
http://aminet.net/search?query=icon+type
I'm surprised there is no standard AmigaDOS command to do this, but hopefully the above holds the ticket.
EDIT: This should do it, but it can't accept wildcards and/or recurse drawers, so with a little help from the "LIST" command to do that job.....
http://aminet.net/package/util/wb/icontype