Just as another fact, in japan, a dickgirl drawing is called futa. It is easy to find these drawings now, but it is a bit more difficult to find one that resembles a transformation into one.
Here are some more that I have found:
(My personal favorite) Momohime:
http://process.gtsdepot.net/forum/showthread.php?t=408
The Noble Illusianist:
http://process.gtsdepot.net/forum/showthread.php?t=386
Amy's Secret:
http://process.gtsdepot.net/forum/showthread.php?t=316
Like a Leech:
http://process.gtsdepot.net/forum/showthread.php?t=464
Omottaijyou (Great Reaction In Ecstasy):
http://process.gtsdepot.net/forum/showthread.php?t=1005
Girl to Love Zamock:
http://process.gtsdepot.net/forum/showthread.php?t=833