Good luck in finding one of those!
I've been looking for quite a while to no avail.
The external solutions, while not readily available, are much more likely to pop up than the internal solution.
Curtis
you can also try http://www.amibay.com
Why external? i had a ICD internal IDE controller for my A500. Used it with a 3.5" quantum and i had it mounted internally. Worked well with WB 1.3.