>
> Payment protocol just doesn't well the use cases of,
> * an on-going payment stream from, e.g. Eligius to coinbase
> * deposit addresses and deposit situations


This seems to be the key point of disagreement here. Wladimir and I think
it satisfies your requirement just fine. You disagree. Let's get to the
bottom of that.

A PaymentRequest with a zero valued pay-to-address output and an expiration
time, base58 encoded, would look very much like your extended address form.
I don't suggest anyone actually represents PaymentRequest's using base58
but it helps to see the conceptual analogue. There'd be a bit more stuff in
there like some varint and wiretype codes but we're talking a handful of
bytes. Functionally, it'd be identical.

Places like protocols or APIs that require a piece of text and cannot
handle a piece of binary data could be retrofitted into the new world by
accepting base58 encoded PaymentRequest's. This would be kind of silly
because it's fundamentally binary data, but we already do this so it's at
least consistently silly :)