BIP 11 makes M-of-N multi-sig transactions standard --- for N <= 3. What is the current support among miners for the multi-sig transactions with N > 3? (say 3-of-6). Also, BIP 11 states:
The current Satoshi bitcoin client does not relay or mine transactions with scriptSigs larger than 200 bytes; to accomodate 3-signature transactions, this will be increased to 500 bytes.
Does this still hold, and if yes, does this limit come into play for N > 3 or M > 3? What other obstacles are in the way of standardizing M-of-N for meaningful N?