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.
Maybe you could allow 12 OR 24 words. 24 words allow for safe (??) and simple key splitting.
Probably there will have to be an option or some way to tell the program whether the seed is old or new... or will the new seed have a different number of words?