Is it possible to create a type of redemption script that when the correct number of signatures are collected pays out to a pre-defined address ?
I believe this is possible, but with a subtle difference to how OP suggests.
OP seems to want: funds are first signed off by the multisig address, then a transaction is broadcast moving the funds to [destination].
It's not possible for a destination script to stipulate where the funds can end up. A new opcode could introduce that feature, but we can do this a different way.
I would argue this no weaker than having a transaction between the two destinations (as OP envisioned). In either case the multisig participants could hold the funds to ransom before the end user can move them.
Multisig: 2 [pubkey1] [pubkey2] 3 CHECKMULTISIG Destination: DUP HASH160 [hash] EQUALVERIFY CHECKSIG
Since we cannot lock funds so they are released to a certain destination, we just merge the two scripts, allowing predefined party to take control only when the multisig is solved. He would propose a spend to the others, they sign, then he signs (it can be done in any order)
The scriptPubKey (or P2SH script) would then look like this:
2 [pubkey1] [pubkey2] 3 CHECKSIG DUP HASH160 [hash] EQUALVERIFY CHECKSIG
And the scriptSig:
[sig1] [sig2] [sigA] [pubkeyA]