Baz
I dont quite understand, the question, do you want the whole quill to be cream? or just half of it like normal?
If you still want it to look segmented, then have you tried stripping standard eye herl and then varnishing it and winding it over a white thread base whilst still wet? It may take on the colour of the thread, I know if you leave a tiny gap between the windings of the thread showing through, then you can extend the paler section of the quill.
This is how i tie Quill Diawl bachs in various colours (i do use dyed eyes though, but they are translucent when wet).
never seen eyes dyed cream or white though.
Sandy