Pardon me if this has been posted in the past (sometimes the "search" function isn’t so user friendly) - I found this short book online called "A classified list of early American bookplates":
http://books.google.com/books?id=0fMuAAAAMAAJ&oe=UTF-8
It only has a few illustrations, but most of them are heraldic.
If not still under copyright, this (or at least the heraldic examples) would IMO make a nice addition to add to our home page.
I’ve been thinking about adding them as links from the Roll of Early American Arms.
That would probably be a nice addition.
I went through the book’s list hoping to find some missing arms of Declaration/Constitution signers, but to no avail.