I am interested in fixed pseudo-random permutation algorithms that are defined for any number of words in the input (but there might be some minimal number of words, e.g. 8), where the word size may be 8/16/32/64 bits. Such permutation may be used as the core function in sponge construction for hashing the message.
The only example that I have found is MD6 core function (although it may be slow, and I don't know if it can be used as a basis of the sponge construction).
Are there any newer (maybe experimental, with unknown cryptographical security) algorithms that match the above requirements?