On a related question, will seeds that are more than 12 words (and multiples of 3) always be supported? It came up in this thread where hobbes talks about concatenating 2 wallet seeds to create a 24 word seed:
https://bitcointalk.org/index.php?topic=354261.0in version 2.0, the seed phrase will be hashed in order to generate the master public key.
thus, any phrase length will be supported.
However, in order to recognize seeds from version < 2, I plan to check if the number of words is 12.
so it's probably not a good idea to create 24 words seeds now.