[hxgjaaen] Large block ciphers

What is the best parametrizable block cipher which can be expanded to arbitrarily large block sizes and key sizes?

Alternatively, how can one securely construct such ciphers from a smaller cipher, e.g., AES?

Inspired by AES in CBC mode becoming insecure after only 2^64 blocks, a rather small number induced by its fixed 128-bit block size.  Also inspired by Double DES being not more secure than Single DES due to a meet in the middle attack due to its key and block sizes.

There is probably a tricky problem of the minimum number of rounds necessary for an arbitrary given parametrization.