Starting a new topic, because it was starting to be way off-topic.
In another thread, TTBit pointed out an interesting service idea:
Firstbits.com could allow pointing of the address to another, no?
That would be automatic redirection. Mybitcoin already offers payment redirection, but the idea could be generalized.
Let's suppose you want to automatically redirect any payment made from address A to address B. You could run a daemon that knows the private key for address A and automatically forwards to address B any payment made to A. Such a daemon can be an independent piece of software, or simply something that polls bitcoind regularly via JSON-RPC. That would be the self-hosted
For people who can't or don't want to bother running such a daemon locally, someone could provide a service to handle that automatically for you. Of course, you would need to send them the private key, so they would need to prove trustworthy and secure, just like any other online wallet. So all in all, that would be the forward-only online wallet
An optional feature of the online service would be coin mixing/laundering: depending on the situation, you might or might not want people to be aware of the forwarding.