I am currently working on a dark parody of Kafka's metamorphosis where the main character is turning into a horse that focuses on 1. humanity's fear of its own bodies, 2. body horror (consequently), 3. gentrification of the urban ghetto and the objectification of the poor, 4. the desires of thanatos. It takes place in Over-the-Rhine in Cincinnati.
There is plenty of classic literature that treats the subject of transformation and even fetishizes it. Eroticism is not mutually exclusive with regard to expressiveness and import.
You should read 'The Satanic Verses'; the author of the book has been in protective custody ever since its publication due to fatwa ordered for followers of Islam to assassinate him (ironically when the book itself was treating the topic of religious oppression).
To add to your list: "Heart of a Dog" by Mikhail Bulgakov - A famous Russian novel satirizing the Soviet's conception of their archetypal 'new man'. In the novel, a dog is transformed into a human. It even addresses the awkwardness of sexuality across species and in itself.
http://www.academia.edu/5654870/A_Se...ury_Literature
In Peter Singer's treatise on ethics and animal rights "Animal Liberation", he imagines being transformed into a horse and considers self-interested behavior. "Sum" by neuroscientist David Eagleman has a chapter called "Descent of Species".
http://www.davideagleman.com/descent.html
You can also read "The Animal that Therefore I Am" by Derrida, which deconstructs the binary opposition between Human and Animal Other. To plug myself, I have written a great deal on the topic of eroticism and binary oppositions between Human and Animal, and my artwork treats this topic.
http://www.furaffinity.net/user/whiteflamek/
Margaret Atwood has a collection of poetry that deals with Circe, and both Circe and 'transformation' are topics well explored in contemporary poiesis.
Song
My lover Peterson
He named me Goldenmouth
I changed him to a bird
And he migrated south
My lover Frederick
Wrote sonnets to my breast
I changed him to a horse
And he galloped west
My lover Levite
He named me Bitterfeast
I changed him to a serpent
And he wriggled east
My lover I forget
He named me Death
I changed him to a catfish
And he swam north
My lover I imagine
He cannot form a name
I’ll nestle in his fur
And never be to blame.
-Leonard Cohen,
from Let Us Compare Mythologies
Sitting in a Small Screenhouse on a Summer Morning
Ten more miles, it is South Dakota.
Somehow, the roads there turn blue,
When no one walks down them.
One more night of walking, and I could have become
A horse, a blue horse, dancing
Down a road, alone.
I have got this far. It is almost noon. But never mind time:
That is all over.
It is still Minnesota.
Among a few dead cornstalks, the starving shadow
Of a crow leaps to his death.
At least, it is green here,
Although between my body and the elder trees
A savage hornet strains at the wire screen.
He can't get in yet.
It is so still now, I hear the horse
Clear his nostrils.
He has crept out of the green places behind me.
Patient and affectionate, he reads over my shoulder
These words I have written.
He has lived a long time, and he loves to pretend
No one can see him.
Last night I paused at the edge of darkness,
And slept with green dew, alone.
I have come a long way, to surrender my shadow
To the shadow of a horse.
-James Wright