I have been experimenting with using UUIDs as database keys. I want to take up the least amount of bytes as possible, while still keeping the UUID representation human read
You don't say what DBMS you're using, but it seems that RAW would be the best approach if you're concerned about saving space. You just need to remember to convert for all queries, or you'll risk a huge performance drop.
But I have to ask: are bytes really that expensive where you live?