Even people with custom tripcodes barely scratch the surface of the possibilities. 56 bit key(8 characters of 7 bits, 8th bit discarded) -> cannot use # character (you only lose a tiny bit here) -> further reduced to something like [0-9a-zA-Z!@$%^&*()-=+;'/.?><:"`~]

Then again, the keyspace really doesn't matter, as the tripcode's pretty tiny too. Honestly, i'm surprised there are not any known collisions.

>>42
Yes, DES has been "broken". The problem is you need a lot of known or chosen plaintexts for the key, and a tripcode always uses the same plaintext (all 0x00) thus that isn't going to help.