CapsNet Generative adversarial network
It is definitely possible to use them in the Encoder (Discriminator) part of a GAN, since according to Hinton's original paper it's used for classification which means it fits in Discriminators as well even though the proper loss function is a subject to research.

I chose a topic of Capsule Nets in Discriminators of GANs for my Master thesis and I'm working on the model right now. However, I simplified the routing algorithm by not vectorizing the DigitCaps values (otherwise Keras code gets complicated, although I'm not sure if what I've done is 100% correct).