I looked through the electrum source code and experimented a little, and this can actually be fixed very easily in the code:
https://github.com/spesmilo/electrum/blob/bc3013caf0d3d6a35290e9cc9e51125b7d03d14c/lib/bitcoin.py#L166

Line 166 :
        is_hex = (len(seed) == 32)

Change to:
        is_hex = ((len(seed) == 32) or (len(seed) == 64))


Line 170:
    return is_hex or (uses_electrum_words and len(words) == 12)

Change to:
    return is_hex or (uses_electrum_words and (len(words) == 12 or len(words) == 24))

Making these two changes allows 256bit hex code w/ to be used again in the style of https://bitcointalk.org/index.php?topic=153990.0

Would this be reasonable?