MD4 is used in ED2k hashes, Tiger is used in TTH hashes. Both are commonly used as identifiers for files in databases. Since ED2k is a hash list and TTH is a merkle tree, they can both be represented using the IPLD format, and the chunks could be addressed via IPFS.
If this would be implemented, it would be very useful since you could "import" foreign hashes to IPFS. You could then rely on some kind of consensus to map these to native IPFS hashes. (256kb chunks, blake2b/sha2)